Pemphigus vulgaris and its subtypesPemphigus is derived from the Greek word pemphix meaning bubble or blister. Pemphigus describes a group ofchronic bullous diseases, originally named by Wichman in 1791. The term pemphigus once included mostbullous eruptions of the skin, but diagnostic tests have improved, and bullous diseases have been reclassified.The term pemphigus refers to a group of autoimmune blistering diseases of the skin and mucous membranescharacterized histologically by intraepidermal blister and immunopathologically by the finding of in vivo boundand circulating immunoglobulin G (IgG) antibody directed against the cell surface of keratinocytes. The 3primary subsets of pemphigus include pemphigus vulgaris, pemphigus foliaceus, andparaneoplastic pemphigusPemphigus vulgaris is an autoimmune, intraepithelial, blistering disease affecting the skin and mucousmembranes and is mediated by circulating autoantibodies directed against keratinocyte cell surfaces. In 1964,autoantibodies against keratinocyte surfaces were described in patients with pemphigus.Intercellular adhesion in the epidermis involves several keratinocyte cell surface molecules. Pemphigusantibody binds to keratinocyte cell surface the molecules desmoglein 1 and desmoglein 3. The binding ofantibody to desmoglein may have a direct effect on desmosomal adherens or may trigger a cellular process thatresults in acantholysis.Patients with the mucocutaneous form of pemphigus vulgaris have pathogenic antidesmoglein 1 andantidesmoglein 3 autoantibodies. Patients with the mucosal form of pemphigus vulgaris have onlyantidesmoglein 3 autoantibodies. Patients with active disease have circulating and tissue-bound autoantibodiesof both the immunoglobulin G1 (IgG1) and immunoglobulin G4 (IgG4) subclasses.History • Mucous membranes: Pemphigus vulgaris presents with oral lesions in 50-70% of patients, and almost all patients have mucosal lesions at some point in the course of their disease. Mucosal lesions may be the sole sign for an average of 5 months before skin lesions develop, or they may be the sole manifestation of the disease. The diagnosis of pemphigus vulgaris should be considered in any patient with persistent oral erosive lesions. • Skin: Most patients with pemphigus vulgaris develop cutaneous lesions. The primary lesion of pemphigus vulgaris is a flaccid blister, which usually arises on healthy-appearing skin but may be found on erythematous skin. New blisters usually are flaccid or become flaccid quickly. Affected skin often is painful but rarely pruritic. • Drug-induced pemphigus vulgaris11 : Drugs reported most significantly in association with pemphigus vulgaris include penicillamine, captopril, cephalosporin, pyrazolones, nonsteroidal anti-inflammatory drugs (NSAIDs), and other thiol-containing compounds. Rifampin, emotional stress, thermal burns, ultraviolet rays, and infections (eg, coxsackievirus, Herpesviridae family) have also been reported as triggers for pemphigus vulgaris.12PhysicalMucous membranes typically are affected first in pemphigus vulgaris. Mucosal lesions may precede cutaneouslesions by weeks or months. Patients with mucosal lesions may present to dentists, oral surgeons, orgynecologists.13 • Mucous membranes • Intact bullae are rare in the mouth. More commonly, patients have ill-defined, irregularly shaped, gingival, buccal, or palatine erosions, which are painful and slow to heal. The erosions extend peripherally with shedding of the epithelium. • The mucous membranes most often affected in pemphigus vulgaris are those of the oral cavity, which is involved in almost all patients with pemphigus vulgaris and sometimes is the only area involved. Erosions may be seen on any part of the oral cavity. Erosions can be scattered and often are extensive. Erosions may spread to involve the larynx, with subsequent hoarseness. The patient often is unable to eat or drink adequately because the erosions are so uncomfortable.
• In juvenile pemphigus vulgaris, stomatitis is the presenting complaint in more than 50% of the cases. • Other mucosal surfaces may be involved, including the conjunctiva,14 esophagus (causes odynophagia and/or dysphagia),15 labia, vagina, cervix, vulva,16 penis, urethra, nasal mucosa, and anus.• Skin • The primary lesion of pemphigus vulgaris is a flaccid blister filled with clear fluid that arises on healthy skin or on an erythematous base, as shown in the images below. • Early, small blister filled with clear fluid arises on healthy skin. • Flaccid blister filled with clear fluid arises on healthy skin. • The blisters are fragile; therefore, intact blisters may be sparse. The contents soon become turbid, or the blisters rupture, producing painful erosions, which is the most common skin presentation and is shown in the image below. Erosions often are large because of their tendency to extend peripherally with the shedding of the epithelium. • An erosion. Vegetating pemphigus vulgaris: Ordinary pemphigus vulgaris erosions may develop • vegetation. Lesions in skin folds readily form vegetating granulations. In some patients, erosions tend to develop excessive granulation tissue and crusting, and these patients display more vegetating lesions. This type of lesion tends to occur more frequently in intertriginous areas and on the scalp or face. The vegetating type of response can be more resistant to therapy and can remain in one place for long periods.• Nails: Acute or chronic paronychia, subungual hematomas, and nail dystrophies affecting one or several fingers or toes have been reported with pemphigus vulgaris.17,18 Patients with paronychial pemphigus usually also have oral involvement.
• Pemphigus in pregnancy: Pemphigus vulgaris occurring in pregnancy is rare. When present, maternal autoantibodies may cross the placenta, resulting in neonatal pemphigus. Neonatal pemphigus is transient and improves with clearance of maternal autoantibodies.19 Treatment of pemphigus vulgaris in pregnancy is with oral corticosteroids; however, prednisone and its metabolites cross the placenta and have been associated with low birth weight, prematurity, infection, and adrenal insufficiency. • Nikolsky sign: In patients with active blistering, firm sliding pressure with a finger separates normal- appearing epidermis, producing an erosion. This sign is not specific for pemphigus vulgaris and is found in other active blistering diseases. • Asboe-Hansen sign: Lateral pressure on the edge of a blister may spread the blister into clinically unaffected skin.Age: Peak age of onset is from 50-60 years. Infants with neonatal pemphigus remit with clearance ofmaternal autoantibodies. The disease may develop in children or in older persons. • Disease association: Pemphigus occurs in patients with other autoimmune diseases, particularly myasthenia gravis and thymoma.Treatment: PrednisoneMay decrease inflammation by reversing increased capillary permeability and suppressing PMN activity.Immunosuppressive agentsUseful adjuvants in patients with pemphigus vulgaris with generalized disease unresponsive to steroids and/orother anti-inflammatory agents or in patients unable to tolerate prednisone.Azathioprine (Imuran)Antagonizes purine metabolism and inhibits synthesis of DNA, RNA, and proteins.
3. Erythema multiforme, Stevens Johnsonsyndrome, Lyell’s syndromeErythema multiforme is a skin condition of unknown cause, possibly mediated by deposition of immunecomplex (mostly IgM) in the superficial microvasculature of the skin and oral mucous membrane that usuallyfollows an infection or drug exposure. It is a common disorder, with peak incidence in the second and thirddecades of life.The condition varies from a mild, self-limited rash (E. multiforme minor) to a severe, life-threatening formknown as erythema multiforme major (or erythema multiforme majus) that also involves mucousmembranes. This severe form may be related to Stevens-Johnson syndrome. The mild form is far morecommon than the severe form. Diagnosis is confirmed by biopsy.The mild form usually presents with mildly itchy, pink-red blotches, symmetrically arranged and starting on theextremities. It often takes on the classical "target lesion" appearance, with a pink-red ring around a palecenter. Resolution within 7–10 days is the norm.Individuals with persistent (chronic) erythema multiforme will often have a sore form at an injury site, eg. aminor scratch or abrasion, within a week. Irritation or even pressure from clothing will cause the erythema soreto continue to expand along its margins for weeks or months, long after the original sore at the center heals.The most common predisposing infection is Herpes simplex, but bacterial infections (commonly Mycoplasma)and fungal diseases are also implicated. It has been shown that Herpes simplex virus suppression and evenprophylaxis (with acyclovir) can prevent recurrent erythema multiforme eruption.Other causes include drug reactions, most commonly to sulfa drugs, phenytoin, barbiturates, penicillin,and allopurinol, or a host of internal ailments.Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are two forms of a life-threatening condition affecting the skin in which cell death causes theepidermis to separate from the dermis.The syndrome is thought to be a hypersensitivity complex affecting the skin and the mucous membranes.Although the majority of cases are idiopathic, the main class of known causes is medications, followed byinfections and (rarely) cancers.There is agreement in the medical literature that Stevens–Johnson syndrome (SJS) can be considered a milderform of toxic epidermal necrolysis (TEN). These conditions were first recognised in 1922Both diseases can be mistaken for erythema multiforme. Erythema multiforme is sometimes caused by areaction to a medication but is more often a type III hypersensitivity reaction to an infection (caused most oftenby Herpes simplex) and is relatively benign. Although both SJS and TEN can also be caused by infections, theyare most often adverse effects of medications. Their consequences are potentially more dangerous than thoseof erythema multiforme.SJS usually begins with fever, sore throat, and fatigue, which is misdiagnosed and usually treated withantibiotics. Ulcers and other lesions begin to appear in the mucous membranes, almost always in the mouthand lips but also in the genital and anal regions. Those in the mouth are usually extremely painful and reducethe patients ability to eat or drink. Conjunctivitis of the eyes occurs in about 30% of children who develop SJS.A rash of round lesions about an inch across arises on the face, trunk, arms and legs, and soles of the feet, butusually not the scalpSJS is thought to arise from a disorder of the immune systemIt can be caused by infections (usually following infections such as herpes simplex virus, influenza, mumps, cat-scratch fever, histoplasmosis, Epstein-Barr virus,mycoplasma pneumoniae or similar).Although Stevens–Johnson Syndrome can be caused by viral infections, malignancies or severe allergicreactions to medication, the leading cause appears to be the use of antibiotics and sulfa drugs.Medications that have traditionally been known to lead to SJS, erythema multiforme and toxic epidermalnecrolysis
include sulfonamides (antibiotics), penicillins (antibiotics), barbiturates (sedatives), lamotrigine andphenytoin (e.g. Dilantin) (anticonvulsants). Combining lamotrigine with sodium valproate increases the risk of SJS.SJS constitutes a dermatological emergency. All medications should be discontinued, particularly those knownto cause SJS reactions.Initially, treatment is similar to that for patients with thermal burns, and continued care can only be supportive(e.g. intravenous fluids and nasogastric or parenteral feeding) and symptomatic (e.g. analgesic mouth rinsefor mouth ulcer). Dermatologists and surgeons tend to disagree about whether the skin should be debrided.Beyond this kind of supportive care, there is no accepted treatment for SJS. Treatment with corticosteroids iscontroversial.Toxic epidermal necrolysis (also known as "Lyells syndrome") is a rare, life-threatening dermatological condition that is usually induced by a reaction to medications. It is characterizedby the detachment of the top layer of skin (the epidermis) from the lower layers of the skin (the dermis) all overthe body.There is broad agreement in medical literature that TEN can be considered a more severe form of Stevens-Johnson syndrome, and debate whether it falls on a spectrum of disease that includes erythema multiformeTEN affects many parts of the body, but it most severely affects the mucous membranes, such asthe mouth, eyes, and vagina. The severe findings of TEN are often preceded by 1 to 2 weeks of fever. Thesesymptoms may mimic those of a common upper respiratory tract infection. When the rash appears it may beover large and varied parts of the body, and it is usually warm and appears red. The dermal layer fills with fluidbeing deposited there by the bodys immune system, usually as a result of a negative reaction to an antibiotic.The skin then begins to sag from the body and can be peeled off in great swaths. The mouth becomes blisteredand eroded, making eating difficult and sometimes necessitating feeding through a nasogastric tube through thenose or a gastric tube directly into the stomach. The eyes are affected, becoming swollen, crusted, andulcerated and blindness may occur.Toxic epidermal necrolysis is a rare and usually severe adverse reaction to certain drugs. History of medicationuse exists in over 95% of patients with TEN. The drugs most often implicated in TEN are antibiotics such assulfonamides, nonsteroidal anti-inflammatory drugs, allopurinol, antimetabolites (methotrexate), antiretroviraldrugs, corticosteroids, chlormezanone (anxiolytic) and anticonvulsants suchas phenobarbital,phenytoin, carbamazepine, and valproic acid.The condition might also result from infection with agents such as Mycoplasma pneumoniae or the herpesvirus; and transplants of bone marrow or organsMicroscopically, TEN causes cell death throughout the epidermis. Keratinocytes, which are the cells foundlower in the epidermis, specializing in holding the skin cells together, undergo necrosis (cell death).Often, the diagnosis can be made clinically. Generally, if the clinical history is consistent with Stevens-Johnsonsyndrome, and the skin lesion covers greater than 30% of the body surface area, the diagnosis of TEN isappropriate. Sometimes, however, examination of affected tissue under the microscope may be needed todistinguish it between other entities such as staphylococcal scalded skin syndrome. Typical histological criteriaof TEN include mild infiltrate of lymphocytes which may obscure the dermoepidermal junction and prominentcell death with basal vacuolar change and individual cell necrosis.Nikolskys sign is almost always present in toxic epidermal necrolysisThe first line of treatment is early withdrawal of culprit drugs, early referral and management in burnunits or intensive care units, supportive management, and nutritional support.The second line is Intravenous immunoglobulin (IVIG)
The mortality for toxic epidermal necrolysis is 30-40 per cent. Loss of the skin leaves patients vulnerable toinfections from fungi and bacteria, and can result in sepsis, the leading cause of death in the disease.Deathis caused either by infection or by respiratory distress which is either due to pneumonia or damage to thelinings of the airway
6. ErysipelasErysipelas is a superficial bacterial skin infection that characteristically extends into the cutaneous lymphatics.Historically, erysipelas occurred on the face and was caused by Streptococcus pyogenes.However, a shift in thedistribution and etiology of erysipelas has occurred, with most erysipelas infections now occurring on the legsand with non–group A streptococci sometimes being identified as the etiologic agents.Bacterial inoculation into an area of skin trauma is the initial event in developing erysipelas. Thus, local factors,such as venous insufficiency, stasis ulcerations, inflammatory dermatoses, dermatophyte infections, insectbites, and surgical incisions, have been implicated as portals of entry. The source of the bacteria in facialerysipelas is often the hosts nasopharynx, and a history of recent streptococcal pharyngitis has been reportedin up to one third of cases. Other predisposing factors include diabetes, alcohol abuse,1 HIV infection,nephrotic syndrome, other immunocompromising conditions, and vagrant lifestyle.Preexisting lymphedema is a clear-cut risk factor for erysipelas.Patients often cannot recall an inciting event, but a history of recent trauma or pharyngitis may be elicited.Prodromal symptoms, such as malaise, chills, and high fever, often begin before the onset of the skin lesionsand usually are present within 48 hours of cutaneous involvement. Pruritus, burning, and tenderness are typicalcomplaints.PhysicalErysipelas begins as a small erythematous patch that progresses to a fiery-red, indurated, tense, and shinyplaque, as shown in the image below. Facial erysipelas exhibiting classic fiery-red plaque with raised, well-demarcated borders. The lesion classically exhibits raised sharply demarcated advancing margins. Local signs of inflammation, such as warmth, edema, and tenderness, are universal. Lymphatic involvement often is manifested by overlying skin streaking and regional lymphadenopathy. More severe infections may exhibit numerous vesicles and bullae along with petechiae and even frank necrosis. Streptococci cause most cases of erysipelas; thus, penicillin has remained first-line therapy.8,9 Penicillin administered orally or intramuscularly is sufficient for most cases of classic erysipelas and should be given for 10-20 days. • A first-generation cephalosporin or macrolide, such as erythromycin or azithromycin, may be used if the patient has an allergy to penicillin. Cephalosporins may cross-react with penicillin and should be used with caution in patients with a history of severe penicillin allergy such as anaphylaxis.
10) Types Of Contact Dermatitis:Contact dermatitis is a term for a skin reaction (dermatitis) resulting from exposureto allergens (allergic contact dermatitis) or irritants (irritant contact dermatitis).Phototoxic dermatitisoccurs when the allergen or irritant is activated by sunlight.Contact dermatitis is a localized rash or irritation of the skin caused by contact with a foreignsubstance. Only the superficial regions of the skin are affected in contact dermatitis. Inflammation ofthe affected tissue is present in the epidermis (the outermost layer of skin) and the outer dermis (thelayer beneath the epidermis). Unlikecontact urticaria, in which a rash appears within minutes ofexposure and fades away within minutes to hours, contact dermatitis takes days to fade away. Eventhen, contact dermatitis fades only if the skin no longer comes in contact with the allergen or irritant. Contact dermatitis results in large, burning, and itchy rashes, and these can take anywhere fromseveral days to weeks to heal. Chronic contact dermatitis can develop when the removal of theoffending agent no longer provides expected relief.There are three types of contact dermatitis: irritant contact dermatitis, allergic contact dermatitis, andphotocontact dermatitis. Photocontact dermatitis is divided into two categories that is, phototoxic andphotoallergic.Irritant contact dermatitisIrritant contact dermatitis can be divided into forms caused by chemical irritants and those caused byphysical irritants. Common chemical irritants implicated include solvents (alcohol, xylene, turpentine,esters,acetone, ketones, and others); metalworking fluids (neat oils, water-based metalworking fluidswith surfactants); latex; kerosene; ethylene oxide; surfactants in topical medications and cosmetics(sodium lauryl sulfate); alkalies (drain cleaners, strong soap with lye residues). Physical irritant contactdermatitis may most commonly be caused by low humidity from air conditioning. Also,many plants are directly irritating the skin.Allergic contact dermatitisAlthough less common than ICD, ACD (Allergic Contact Dermatitis) is accepted to be the mostprevalent form of immunotoxicity found in humans. By its allergic nature, this form of contactdermatitis is a hypersensitive reaction that is atypical within the population. The mechanisms by whichthese reactions occur are complex, with many levels of fine control. Their immunology centres aroundthe interaction of immunoregulatory cytokines and discrete subpopulations of T lymphocytes. Allergensinclude nickel, goldPhotocontact dermatitisivided into two categories, phototoxic and photoallergic, PCD is the eczematous condition which istriggered by an interaction between an otherwise unharmful or less harmful substance on the skin andultraviolet light (320-400 nm UVA) therefore manifesting itself only in regions where the sufferer hasbeen exposed to such rays. Without the presence of these rays, the photosensitiser is not harmful.For this reason, this form of contact dermatitis is usually associated only with areas of skin which areleft uncovered by clothing.
Allergic dermatitis is usually confined to the area where the trigger actually touched the skin, whereasirritant dermatitis may be more widespread on the skin. Symptoms of both forms include the following: • Red rash. This is the usual reaction. The rash appears immediately in irritant contact dermatitis; in allergic contact dermatitis, the rash sometimes does not appear until 24–72 hours after exposure to the allergen. • Blisters or wheals. Blisters, wheals (welts), and urticaria (hives) often form in a pattern where skin was directly exposed to the allergen or irritant. • Itchy, burning skin. Irritant contact dermatitis tends to be more painful than itchy, while allergic contact dermatitis often itches.While either form of contact dermatitis can affect any part of the body, irritant contact dermatitis often affects thehands, which have been exposed by resting in or dipping into a container (sink, pail, tub, swimming pools withhigh chlorine) containing the irritant.Self-care at home • Immediately after exposure to a known allergen or irritant, wash with soap and cool water to remove or inactivate most of the offending substance. • Weak acid solutions [lemon juice, vinegar] can be used to counteract the effects of dermatitis contracted by exposure to basic irritants. • If blistering develops, cold moist compresses applied for 30 minutes 3 times a day can offer relief. • Calamine lotion and cool colloidal oatmeal baths may relieve itching. • Oral antihistamines such as diphenhydramine (Benadryl, Ben-Allergin) can also relieve itching. • For mild cases that cover a relatively small area, hydrocortisone cream in nonprescription strength may be sufficient. • Avoid scratching, as this can cause secondary infections. • A barrier cream such as those containing zinc oxide (e.g. Desitin, etc.) may help to protect the skin and retain moisture.Medical careIf the rash does not improve or continues to spread after 2-3 of days of self-care, or if the itching and/or pain issevere, the patient should contact a dermatologist or other physician or physician assistant. Medical treatmentusually consists of lotions, creams, or oral medications. • Corticosteroids. A corticosteroid medication similar to hydrocortisone may be prescribed to combat inflammation in a localized area. This medication may be applied to your skin as a cream or ointment. If the reaction covers a relatively large portion of the skin or is severe, a corticosteroid in pill or injection form may be prescribed. • Antihistamines. Prescription antihistamines may be given if nonprescription strengths are inadequate.Since contact dermatitis relies on an irritant or an allergen to initiate the reaction, it is important for thepatient to identify the responsible agent and avoid it. This can be accomplished by having patch tests,a method commonly known as allergy testing. The patient must know where the irritant or allergen isfound to be able to avoid it.
11) Atopic DermatitisAtopic dermatitis (AD; a type of eczema) is an inflammatory, chronically relapsing, non-contagiousand pruritic skin disorder.The skin of a patient with atopic dermatitis reacts abnormally and easily to irritants, food, andenvironmental allergens and becomes red, flaky and very itchy. It also becomes vulnerable to surfaceinfections caused by bacteria. The skin on the flexural surfaces of the joints (for example inner sides ofelbows and knees) are the most commonly affected regions in people.Atopic dermatitis often occurs together with other atopic diseases like hay fever, asthma and allergicconjunctivitis. It is a familial and chronic disease and its symptoms can increase or disappear over time. Atopicdermatitis in older children and adults is often confused with psoriasis. Atopic dermatitis afflicts humans,particularly young children; it is also a well-characterized disease in domestic dogs.Although there is no cure for atopic eczema, and its cause is not well understood, it can be treated veryeffectively in the short term through a combination of prevention (learning what triggers the allergic reactions)and drug therapy.Atopic dermatitis most often begins in childhood before age 5 and may persist into adulthood. For some, itflares periodically and then subsides for a time, even up to several yearsAlthough atopic dermatitis can theoretically affect any part of the body, it tends to be more frequent onthe hands and feet, on the ankles, wrists, face, neck and upper chest. Atopic dermatitis can also affectthe skin around the eyes, including the eyelidsn most patients, the usual symptoms that occur with this type of dermatitis are aggravated bya Staphylococcus aureus infection, dry skin, stress,low humidity and sweating, dust or sand or cigarette smoke. Also, the condition can be worsened byhaving long and hot baths or showers, solvents, cleaners or detergents and wool fabrics or clothing.Atopic dermatitis is also known as infantile eczema, when it occurs in infants. Infantile eczema may continueinto childhood and adolescence and it often involves an oozing, crusting rash mainly on the scalp and face,although it can occur anywhere on the bodySymptoms may vary from person to person but they are usually present as a red, inflamed, and itchyrash and can quickly develop into raised and painful bumps. The first sign of atopic dermatitis is thered to brownish-gray colored patches that are usually very itchy. Itching may become more intenseduring the night. The skin may present small and raised bumps which may be crusting or oozing ifscratched, which will also worsen the itch. The skin tends to be more sensitive and may thicken, crackor scale.When appearing in the area next to the eyes, scratching can cause redness and swelling around them andsometimes, rubbing or scratching in this area causes patchy loss of eyebrow hair and eyelashes.The symptoms of atopic dermatitis vary with the age of the patients. Usually, in infants, the condition causesred, scaly, oozy and crusty cheeks and the symptoms may also appear on their legs, neck and arms.Symptoms clear in about half of these children by the time they are 2 or 3 years old. In older children, thesymptoms include dry and thick, scaly skin with a very persistent itch, which is more severe than in infants.Since there is no cure for atopic eczema, treatment should mainly involve discovering the triggers ofallergic reactions and learning to avoid them.
The primary treatment involves prevention, includes avoiding or minimizing contact with (or intake of)known allergens. Once that has been established, topical treatments can be used. Topical treatmentsfocus on reducing both the dryness and inflammation of the skin.To combat the severe dryness associated with atopic dermatitis, a high-quality, dermatologist-approvedmoisturizer should be used daily. Moisturizers should not have any ingredients that may further aggravate thecondition. Moisturizers are especially effective if applied 5–10 minutes after bathing. As a rule of thumb thethicker the moisturizer the better it is at retaining moisture. Petroleum jelly is considered one of the mosteffective moisturizers by reducing transepidermal water loss by up to 98%If moisturizers on their own dont help and the eczema is severe, a doctor may prescribetopical corticosteroid ointments, creams, or injections. Corticosteroids have traditionally beenconsidered the most effective method of treating severe eczema. Disadvantages of using steroidcreams include stretch marks and thinning of the skin.Atopy is an allergic hypersensitivity affecting parts of the body not in direct contact withthe allergen. A familial predisposition to a localized reaction.Atopy is a disease characterized by a tendency to be “hyperallergic”. Atopy is a word taken from theGreek meaning “special” or “unusual”. A patient with atopic allergies has atopic eczema or atopicdermatitis since infancy. Atopic eczema is an extremely itchy skin condition with a hallmark rash thatappears most often over the flexural regions (e.g., back of knees, crook of elbows) but can involvealmost every region of the body. Crusty, scaly, flattened, erythematous lesions of atopic eczema canappear almost everywhere, but are worse in certain areas or after exposure to certain irritants orallergens (e.g., washing hands with a perfumed or otherwise allergenic soap, wearing a wool orscratchy sweater or skirt, rolling across freshly cut lawns). The single most important featureassociated with atopic eczema lesions is that they are extremely itchy, and the itch can occur evenbefore the lesions erupt on the skin and are visible.It is localized immediate hypersensitivity reaction to an allergen. It may involve eczema (atopicdermatitis [AD]), allergic conjunctivitis, allergic rhinitis and asthma. There appears to be astrong hereditary component. One study concludes that "the general risk of developing AD (3%) andatopy (7%) increases by a factor of two with each first-degree family member already suffering fromatopy." Environmental factors are also known to play a major role and the hygiene hypothesis isone of the best paradigms available to date to explain the steep rise observed in atopic diseases. Thissupports that it is the excess cleanliness of our environments that has led to the decline in thenumber of infectious stimuli that are necessary for the proper development of our immune system.Patients with atopic eczema usually develop what is referred to as the “allergic triad” of symptoms i.e.,eczema, hayfever, and asthma. They also have a tendency to have food allergies, and othersymptoms characterized by their hyperallergic state. For example, eosinophilic esophagitis is foundassociated with atopic allergies. Atopy and atopic eczema can be considered a genetic diseasebecause of its strong genetic component, but atopy does not segregate like an autosomal dominanttrait. There are certain environmental factors that contribute to its appearance in infants and children,but the underlying cause is a genetic tendency to be hyperallergic. Atopic eczema cannot beprevented in infants because of its genetic origins.Atopic syndrome can be fatal for those who experience serious allergic reactions, such as anaphylaxis, broughton by reactions to food or environment.The individual components are all caused at least in part by allergy (type I hypersensitivity reactions). Theseresponses appear after the body is exposed to various allergens, for example specific kinds offood,pollen, dander or insect venoms. Although atopy has various definitions, most consistently it is defined bythe presence of elevated levels of total and allergen-specific IgE in the serum of patient, leading to positiveskin-prick tests to common allergens.
22) Skin in Systemic diseaseThyrotoxicosis may lead to multiple cutaneous manifestations, including hair loss, pretibial myxedema,onycholysis and acropachy. In patients with hypothyroidism, there is hair loss, the skin is cold and pale, withmyxedematous changes, mainly in the hands and in the periorbital region. The striking features of Cushingsyndrome are centripetal obesity, moon facies, buffalo hump, supraclavicular fat pads, and abdominal striae. InAddison disease, the skin is hyperpigmented, mostly on the face, neck and back of the hands. Virtually allpatients with acromegaly have acral and soft tissue overgrowth, with characteristic findings, like macrognathiaand enlarged hands and feet. The skin is thickened, and facial features are coarser. Conditions leading tohyperandrogenism in females present as acne, hirsutism and signs of virilization (temporal balding,clitoromegaly).A prominent feature of hypopituitarism is a pallor of the skin with a yellowish tinge. The skin isalso thinner, resulting in fine wrinkling around the eyes and mouth, making the patient look older. Primaryhyperparathyroidism is rarely associated with pruritus and chronic urticaria. In hypoparathyroidism, the skin isdry, scaly and puffy. Nails become brittle and hair is coarse and sparse. Pseudohypoparathyroidism may havea special somatic phenotype known as Albright osteodystrophy. This consists of short stature, short neck,brachydactyly and subcutaneous calcifications. Some of the cutaneous manifestations of diabetes mellitusinclude necrobiosis lipoidica diabeticorum, diabetic dermopathy, scleredema adultorum and acanthosisnigricans.Dermatologic Manifestations of Hematologic Diseasehttp://emedicine.medscape.com/article/1096183-overview
29) Paraneoplastic Diseaseshttp://emedicine.medscape.com/article/1095113-overviewA wide range of cutaneous signs may be related to internal malignancy. Cancer may manifest inthe skin as metastasis (eg, leukemia cutis, cutaneous T-cell lymphoma, Paget disease of thebreast), nonspecific metabolic effects related to inanition (eg, wasting, alopecia, xerosis), infectionsrelated to immunosuppression (eg, herpes zoster), signs resulting from compromise or dysfunctionof the affected organ (eg, jaundice), or diverse dermatologic entities called paraneoplasticsyndromes, which signal that a remote malignancy is present. Cutaneous manifestations maydevelop before a diagnosis of malignancy is determined; thus, these findings may aid the physicianin the early identification of malignancy.Acanthosis nigricans (AN) manifests as a hyperpigmented, velvety thickening of the skin thatusually occurs in the intertriginous zones, including the axillae, groin, neck, and inframammaryfolds. AN may develop in areas subjected to trauma, such as the extensor surfaces of the kneesand elbows. As many as 30% of patients also have papillomatous thickening of the oral mucosa.The subset of patients with AN associated with malignancies also has skin changes involving thescalp, areolae, and eyelids.DermatomyositisDM is an inflammatory proximal myopathy with characteristic skin changes; it is often associated with anoccult malignancy. The rash is characteristic and diagnostic and usually accompanies or precedes the onset ofthe myopathy.Skin manifestations include the following: • Heliotrope rash (so named because of the similarity to the color of the blue-purple flower, the heliotrope) on the upper eyelids • Periorbital edema • A macular red rash on the face and the V of the upper trunk that may become shiny and atrophic, with variable pigmentation and telangiectasias (poikiloderma) • Violaceous scaly papules over the interphalangeal and metacarpophalangeal joints (ie, Gottron papules) that evolve into atrophic telangiectatic maculesSweet SyndromeIn 1964, Robert Sweet, MD, described a syndrome involving an acute onset of febrile neutrophilicdermatosis in 8 women he encountered over a 15-year period. At the time, the classic patient was a middle-aged woman in good general health whose skin lesions developed within days of an upper respiratory tractinfection or minor illness. While this entity came to be known by the eponym Sweet syndrome, it has nowbeen expanded to include older patients with an underlying internal malignancy. Fever, neutrophilia, andsterile erythematous plaques or nodules that respond to steroid therapy manifest it. Skin lesions mostcommonly involve the upper extremities and face and begin as tender, erythematous plaques or nodules. Thelesions may evolve into vesicles, bullae, or pustules. Extracutaneous manifestations are not infrequent andcommonly involve the eyes, lungs, liver, kidneys, muscles, and bones. Laboratory features includeneutrophilia, anemia, and an elevated erythrocyte sedimentation rate.Diagnosis is based on the clinical presentation and characteristic findings at skin biopsy. Histologicevaluation reveals a neutrophilic infiltrate in the dermis, without evidence of infection, vasculitis, ormalignant cells. Patients frequently have a positive perinuclear antineutrophil cytoplasmic antibody titer.The clinical syndrome can mimic several other entities; the differential diagnoses include erythemamultiforme, cellulitis, and leukemia cutis. Sweet syndrome can usually be distinguished from these otherlesions on the basis of the biopsy results; however, patients are often initially treated for an infectious processbefore the proper diagnosis is realized.Paraneoplastic pemphigus a member of a heterogeneous group of autoimmune paraneoplasticsyndromes. It is characterized by painful, intractable erosive ulcerative stomatitis and apolymorphic cutaneous eruption consisting of erythema, papules, iris lesions, bullae, and erosions.