Psoriasis and scabies by manaswi


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Psoriasis and scabies by manaswi

  2. 2. PSORIASIS  Psoriasis is a common chronic inflammatory skin disorder characterized by recurrent exacerbations and remissions of thickened, erythematous, and scaling plaques.
  3. 3. EPIDEMIOLOGY  Psoriasis, a chronic proliferative skin disease is one of the most common immune mediated disorders occuring in 1.5- 3% of population world wide  Of patients, 75% present with symptoms of psoriasis before age 45yrs  Although rarely life-threatening, psoriasis has an adverse physical and emotional impact on quality of life.
  4. 4. ETIOLOGY  Psoriasis is a complex and multifactorial disease that is apparently associated with interaction between environmental factors (exogenous or endogenous antigens) and a specific genetic background.
  5. 5. ENVIRONMENTAL FACTORS  Factors such as climate, stress, alcohol, smoking, infection, trauma, an d drugs can aggravate psoriasis  Alcohol seems to have a greater influence on the progression of psoriasis in men, and the association between smoking and psoriasis seems to be stronger in women.  Psoriatic lesions can develop at the site of injury on normal appearing skin. This response can be induced by a variety of trauma that includes rubbing, venipuncture, bites, surgery, and mechanical pressure.  Lithium carbonate, β-adrenergic blocking agents, some antimalarial agents, NSAIDS, and
  6. 6. GENETIC FACTORS  There is a significant genetic component in psoriasis, but the exact mode of inheritance is uncertain.  Monozygotic twins have a higher concordance for psoriasis than dizygotic twins.
  7. 7. PATHOPHYSIOLOGY  The three key steps involved in the pathogenesis of psoriasis are i. T-cell activation by antigen in the lymph nodes ii. T-cell binding to the endothelium in the vasculature, with subsequent migration into the dermis and epidermis iii. T-cell reactivation by a second exposure to antigen, which occurs in the dermis. Certain CD4+ and CD8+ T cells have a marker on their cell surface known as cutaneous lymphocyte antigen (CLA) • These CLA-positive T cells are recruited from the circulation and migrate to the skin during inflammatory processes and have been implicated in the pathogenesis of various skin diseases, including psoriasis • For these T cells to become activated, an APC(antigen presenting cell) presents antigen to the T-cell receptor.
  8. 8. Clinical Presentation and Diagnosis  Most patients with psoriasis have symptoms of the disease throughout their lifetime.  Patients who experience frequent relapses, occurring within months or even weeks, tend to develop more severe disease. The palm of one's hand, from the wrist to the fingertips, represents approximately 1% of the body surface area (BSA). Disease affecting less than 2% of the BSA is considered mild, moderate psoriasis involves 3% to 10%, and severe psoriasis involves more than 10% of the BSA.
  9. 9. Psoriasis Vulgaris or Plaque Psoriasis  Psoriasis vulgaris or plaque psoriasis, the most common form of the disease, affects approximately 80% of psoriasis patients.  Lesions are usually distributed in a symmetrical pattern, typically located on the scalp, the lumbar region of the back, and the extensor surfaces of the elbows and knees. The well-demarcated erythematous plaques covered with silvery scales range in diameter from less than 1 cm to 10 cm. The lesions are associated with pain and pruritus and can occasionally crack and bleed. Scale removal may result in punctate bleeding, also called the Auspitz sign.
  10. 10. Guttate Psoriasis  Guttate psoriasis commonly affects children and young adults and is often associated with recent streptococcal infections. The lesions are usually small, scaly, and teardrop-shaped and typically are localized to the trunk, limbs, and scalp.
  11. 11. Inverse Psoriasis  Inverse psoriasis is a form of psoriasis that often exclusively involves the body folds. Lesions usually present in the axillae, groin, inframammary folds, navel, intergluteal crease, and glans penis areas. Inverse psoriasis presents as a large, smooth, dry, and very erythematous lesion. This type of psoriasis is more common in obese patients.
  12. 12. Pustular Psoriasis  Pustular psoriasis is distinguished by the development of white pustules encircled by red skin. The pustules contain noninfectious pus and are usually localized to the palms and soles. Generalized disease affecting the entire body often requires hospitalization and can be fatal.
  13. 13. Erythrodermic Psoriasis  Erythrodermic psoriasis is an acute inflammatory, erythematous, scaling disorder involving the entire skin surface  Severe erythrodermic psoriasis and generalized pustular psoriasis are associated with the loss of the protective functions of the skin. These conditions are life-threatening because of the potential for systemic infections, loss of thermoregulation, and cardiovascular or pulmonary complications.
  14. 14. Psoriatic Arthritis  Psoriatic arthritis is a chronic, progressive, inflammatory arthritis that affects as many as about 30% of patients with psoriasis.207,217 The arthritic symptoms are often associated with the development of skin lesions and include pain, swelling, and stiffness in the joints. Furthermore, approximately 5% to 10% of those patients may experience functional dis- ability.
  15. 15. Psychosocial Aspects  Physical and psychological disability produced by the disease may range from minor to total. Severe psoriasis is associated with substantial morbidity and can cause functional impairment, skin disfigurement, and emotional distress.  Approximately 30% of patients with psoriasis have moderate to severe disease. The prevalence of depression and suicidal ideation among patients with psoriasis is consistent with figures seen in other populations with chronic illness.  Psoriasis directly affects the quality of life and may cause difficulty in work performance, problems with social rejection, sexual dysfunction, and depression.
  16. 16. TREATMENT
  17. 17. NONPHARMACOLOGIC THERAPY  Emollients  Emollients are frequently used during therapy- free periods to minimize skin dryness that can lead to early recurrence.  As lotions, creams, or ointments, emollients often need to be applied several times per day (about four times per day) to achieve a beneficial response. Adverse effects of emollients include folliculitis and allergic or irritant contact dermatitis.
  18. 18.  Balneotherapy  Balneotherapy (and climatotherapy) is a therapeutic approach that consists of bathing in waters containing certain salts, often combined with natural exposure to the sun.
  19. 19. PHARMACOLOGIC THERAPY  Topical treatments  Corticosteroids: beclomethasone, dexamethasone  vitamin D analogues: calciprotriene  Topical Retinoids: Tazarotene  Coal tar  Anthralin  keratolytics  Systemic treatments  Immunosuppressive agents: methotrexate, cyclosporin  Immunomodulatory agents:  Inhibitors of T-cell activation: alefacept, efalizumab  TNF-alpha inhibitors: infliximab, etanercept, adalimumab  Acitretin
  20. 20. Topical Therapy
  21. 21. Systemic therapy
  22. 22. Photo therapy  Ultraviolet – B (UVB):  UVB light( sunburn spectrum, 290-320nm) induces pyramidine dimers, inhibits DNA synthesis and depletes intra epidermal T cells, found in psoriatic epidermis  Heat and humidity from sunlight provide additional positive effects  UVB treatments are administered 3 times weekly  Risks: sunburn, photoaging, and skin cancer
  23. 23. Photochemotherapy  Photochemotherapy combines psoralens with UVA light in the 320 to 400 nm spectrum.  Psoralens: methoxsalen, 8-methoxypsoralen, and trioxsalen.  Psoralens are a group of photoactive compounds that on absorption of UV light, are both antiproliferative and immunomodulatory.  Photochemotherapy is used to control severe, recalcitrant, disabling plaque psoriasis. After 10 to 20 treatments over 4 to 8 weeks, >80% of patients experience clearing of symptoms, which can be maintained with periodic (twice monthly) treatments.  8-Methoxypsoralen (8-MOP) is the most widely used agent, taken at an oral dosage of 0.6 to 0.8 mg/kg of body weight rounded to the nearest 10 mg, 1.25 to 1.5 hours before exposure to UVA light.  ADR: Erythema, blistering, nausea, lethargy, headache, pruritus
  24. 24. SCABIES  Scabies is a contagious pruritic skin infection caused by the mite Sarcoptes scabiei var hominis  Scabies is classified by the World Health Organization as a water-related disease.  The disease may be transmitted from objects but is most often transmitted by direct skin-to-skin contact, with a higher risk with prolonged contact.
  25. 25. Epidemiology  Scabies is 1 of the 6 major epidermal parasitic skin diseases (EPSD) that is prevalent in resource-poor populations, as reported in the Bulletin of the World Health Organization in February 2009.  Prevalence rates are extremely high in aboriginal tribes in Australia, Africa, South America, and other developing regions of the world.  Incidence in parts of Central America and South America and in one Indian village approach 100%.  In 2009 retrospective study of 30,078 children in India, scabies was found to be the second most common skin disease in all age groups of children, and the third most common skin disease in infants.
  26. 26. Symptoms  Pimple-like irritations or a rash  Intense itching, especially at night  Sores caused by scratching
  27. 27. Scabies of the foot Scabies of the hand
  28. 28. Crusted scabies  The elderly and people with an impaired immune system, such as HIV, cancer, or those on immunosuppressive medications, are susceptible to crusted scabies (formerly called Norwegian scabies).On those with a weaker immune system, the host becomes a more fertile breeding ground for the mites, which spread over the host's body, except the face. Sufferers of crusted scabies exhibit scaly rashes, slight itching, and thick crusts of skin that contain thousands of mites. Such areas make eradication of mites particularly difficult, as the crusts protect the mites from topical miticides, necessitating prolonged treatment of these areas.
  29. 29. Crusted scabies in a person with AIDS
  30. 30. Pathophysiology  The entire lifecycle of mites usually lasts 30days within the human epidermis.  After copulation, the male mite dies and female mite burrows into the superficial skin and lays a total of 60-90 eggs. The ova require 10 days to progress through larval and nymph stages to become mature mites.  Mites move through the top layers of the skin by secreting proteases that degrade stratum corneum  They feed on dissolved tissue but donot injest blood.  Scybala (feces) are left behind as they travel through the epidermis, creating linear lessions
  31. 31.  In immunocompromised patients the weak immune response fails to control the disease and results in a fluminant hyper infestation termed crusted scabies  Upon initial infestation, a delayed type-IV hypersensitivity reaction to mites, eggs, or scybala develops over 4-6 weeks.  Previously sensitized individuals can develop symptoms within hours of re exposure.  The hypersensitivity reaction is responsible for the intense pruritus.
  32. 32. Treatment: Scabicidal drugs  Topical agents  Permethrin 5% cream.  Lindane (gamma benzene hexachloride) 1% lotion or cream.  Benzyl benzoate 10% and 25% lotion or emulsion.  Malathion 0.5% lotion.  Monosulfiram 25% lotion.  Crotamiton 10% cream.  Precipitated sulphur 2%–10% ointment.  Esdepallethrine 0.63% aerosol.  Ivermectin 0.8% lotion.  Oral drug  Ivermectin.
  33. 33. Topical agents  Sulphur  Sulphur is the oldest antiscabietic in use. Celsus used sulphur mixed with liquid pitch for management of scabies as early as 25 AD.  Sulphur is used as an ointment (2%–10%) and usually 6% ointment is preferred.  The technique is very simple: after a preliminary bath, the sulphur ointment is applied and thoroughly rubbed into the skin over the whole body for two or three consecutive nights.  ADR: Topical sulphur ointment is messy, malodourous, stains clothing, and in a hot and humid climate may lead to irritant dermatitis
  34. 34.  Benzyl benzoate  It is used as a 25% emulsion and the contact period is 24 hours.  Benzyl benzoate should be applied below the neck three times within 24 hours without an intervening bath.  In young adults or children, the dosage can be reduced to 12.5%.  ADR: Repeated usage may lead to allergic dermatitis.  CI: in pregnant women, lactating women, children less than 2 yrs.
  35. 35.  Crotamiton  Crotamiton (crotonyl-N-ethyl-o-toluidine) is used as 10% cream or lotion.  The best results have been obtained when applied twice daily for five consecutive days after bathing and changing clothes.  Malathion  Malathion is an organophosphate insecticide that irreversibly blocks the enzyme acetylcholinesterase.  Malathion is not recommended nowadays for treatment of human ectoparasitic infestations because of the potential for severe adverse affects.
  36. 36.  Monosulfiram  Monosulfiram emulsion is applied all over the body after a bath, and it should be rubbed in well once a day on two or three consecutive days.  Monosulfiram is chemically related to antabuse and hence alcoholic beverages should be avoided during or soon after treatment.  Soaps containing monosulfiram have been used in the past as a prophylactic measure in infected communities.
  37. 37.  Lindane  It acts on the central nervous system (CNS) of insects and leads to increased excitability, convulsions, and death.  A single six hour application is effective in treatment of scabies. Some authors recommend a repeat application after one week.  Lindane 1% cream or lotion has been found to be very effective in the treatment. It is non-irritating and ease of application has made it a popular treatment.  ADR: it can cause CNS toxicity and rare cases of CNS toxicity, convulsions, and death  Accidental ingestion can lead to lindane poisoning.  The clinical signs of CNS toxicity after lindane poisoning include headache, nausea, dizziness, vomiting, restlessness, tremors, disor ientation, weakness, twitching of eyelids, convulsions, respiratory failure, coma, and death.
  38. 38.  Permethrin  Permethrin is a synthetic pyrethoid and potent insecticide.4 Permethrin is very effective against mites with a low mammalian toxicity.  Permethrin 5% dermal creams are applied overnight once a week for two weeks to the entire body, including the head in infants. The contact period is about eight hours.
  39. 39. Oral antiscabietic agent  Ivermectin  Ivermectin, the 22, 23 dihydro derivative of avermectin B1 is similar to macrolides, but without any antimicrobial action.  MOA: It acts via the suppression of conduction of nerve impulses in the nerve-muscle synapses of insects by stimulation of gamma amino butyric acid from presynaptic nerve endings and enhancement of binding to postsynaptic receptors.  DOSE: Scabies is treated with ivermectin 0.2 mg/kg in a single dose.  ADR:headache, pruritus, pains in the joints and muscles, fever, maculopapular rash, and lymphadenopathy  CI: patients with an allergy to ivermectin and CNS disorders. It is also not indicated during pregnancy, lactation, and in children less than 5 years of age.
  40. 40. Other agents  Allethrin I, widely used as an insect repellent, was effective when used as a spray in scabies.  Thiabendazole 5% cream has been tried in treatment of resistant scabies.