3. Skin Disease
● Skin diseases are common and diverse, ranging
from irritating acne to life-threatening melanoma.
● Dendrite cells help to maintain skin homeostasis by
providing a physical barrier to environmental
insults and by secreting a plethora of cytokines that
influence both the squamous and dermal
microenvironments.
4.
5. Primary skin lesions-
● Macule: A flat, colored lesion, <2 cm in diameter, not raised
above the surface of the surrounding skin
● Patch: A large (>2-cm) flat lesion with a color different from the
surrounding
● Papule: A small, solid lesion, <0.5 cm in diameter, raised above
the surface of the surrounding skin and thus palpable (e.g.,
acne).
● Nodule: A larger (0.5- to 5.0-cm), firm lesion raised above the
surface of the surrounding skin.
● Pustule: A vesicle filled with leukocytes. Note: The presence of
pustules does not necessarily signify the existence of an
infection
6.
7. ● Tumor: A solid, raised growth >5 cm in diameter.
● Plaque: A large (>1-cm), flat-topped, raised lesion; edges may
either be distinct (e.g., in psoriasis) or gradually blend with
surrounding skin (eg eczematous dermatitis).
● Vesicle: A small, fluid-filled lesion, <0.5 cm in diameter, raised
above the plane of surrounding skin. Fluid is often visible, and
the lesions are translucent (e.g., vesicles in allergic contact
dermatitis)
● .Bulla: A fluid-filled, raised, often translucent lesion >0.5 cm in
diameter.
● Wheal: A raised, erythematous, edematous papule or plaque,
usually representing short-lived vasodilation and
vasopermeability
8. Skin Disorder are classified into Five
categories
● Acute Inflammatory dermatoses
● Chronic Inflammatory dermatoses
● Infectious dermatoses
● Blistering (bullous) disorders
● Tumours of skin
9. Acute inflammatory
dermatoses
A disorder involving lesions or eruptions of the skin that are acute
that are lasting for days to weeks.
Example - Urticaria ,Acute eczematous dermatitis,Erythema
multiforme
Eczema is a condition where patches of skin become inflamed,
itchy, red, cracked, and rough.
10. Eczema
Eczema is a clinical term that embraces a number of conditions with varied
underlying etiologies. New lesions take the form of erythematous papules.
Cause – sensitization that develops from skin contact with various agents, plants,
chemical, & metals. Poison ivy and poison oak, dyes used for hair & clothes,
metals, particularly nickel used in jewelry.
S & Sx’s – Vesicles & bullae appear with itching. Scaly crusts form on ruptured
lesions. Oozing plaques.
Scratching – causes the lesions to burst & ooze which spreads the eczema.
TX – Corticosteroids to reduce inflammation.
11. Types of Eczema
• Allergic contact dermatitis—stems from topical exposure to an allergen and is
caused by delayed hypersensitivy reactions.
• Atopic dermatitis—formerly attributed to allergen exposure, now thought to
often stem from defects in keratinocyte barrier function, defined as skin with
increased permeability to substances to which it is exposed, such as potential
antigens
• Drug-related eczematous dermatitis—hypersensitivity reaction to a drug
● Photoeczematous dermatitis—appears as an abnormal reaction to UV or
visible light
12. ● Primary irritant dermatitis—results from exposure to substances that
chemically, physically, or mechanically damage the skin.
Allergic contact dermatitis is triggered by exposure to an environmental
contact-sensitizing agent, such as poison ivy, that chemically reacts
with self-proteins, creating neoantigens that can be recognized by the T
cell arm of adaptive immune system .
14. Urticaria(hives/welts/weals)
● VASCULAR REACTION OF THE SKIN TO AN ALLERGEN
WHEALS – lesions round elevations with red edges & pale
centers extremely itchy
Histamine released – cause blood vessels to dilate, followed by
edema & intense itching
Common causes – food, allergens & stress
TX- steroids, antihistamines, topical creams
15. Pathogenesis
Urticaria (“hives”) is a common disorder mediated by localized
mast cell degranulation, which leads to dermal microvascular
hyperpermeability.
Antigen (Virus,pollens,food etc)+IgE antibodies
(attached to mast cell surface)
Degranulation of mast cell
Granules releases histamine which causes blood
vessels dilation followed by oedema and itching
17. Blistering (bullous) disorder-
a group of disorders in which blisters are the primary and
most distinctive feature.
Example -Pemphigus ,Bulloid pemphigoid ,Dermatitis
herpatiformis
18. Pemphigus -
Pemphigus is an uncommon autoimmune blistering disorder
resulting from loss of normal intercellular attachments within the
epidermis and the squamous mucosal epithelium.
There are three major variants:
• Pemphigus vulgaris (the most common type)
• Pemphigus foliaceus
• Paraneoplastic pemphigus
21. Infectious dermatoses
These are caused by Infections of bacteria , viruses ,fungi
etc
Example - Candida,impetigo etc
Tumours of skin
22. Chronic inflammatory dermatoses
These are persistent skin conditions that exhibit their
most characteristic features over many months to years,
although they may begin with an acute stage.
Example -Psoriasis, Lichen planus, lichen simplex
chronicus
23. Psoriasis
Definition. ----- Derived from ‘psora’ means itching.
Psoriasis is a chronic inflammatory hyperproliferative skin disease.It is a
papulosquamous disorder composed of Erythematous papules and plaques with
overlying silvery scale.
Etiology ------- Idiopathic
● 50% of patient with psoriasis report a positive family history.
● T cells are involved in pathogenesis of psoriasis.
Epidemiology ----- The world wide prevalence of psoriasis is estimated to be
approximately 2-3%
24.
25. Precipitating factors
● Trauma - traumatized area develop psoriasis this phenomenon is
known as Koebner Phenomenon.
● Intercurrent infection
● Stress,Anxiety
● Climate change
● Certain drugs -- beta blockers, antimalarials , Lithium etc.
26. Clinical features-
● Lesions are commonest on the extensor surfaces such as
knees,arms,elbow,legs,sacral gluteal region.
● Scalp involvement
● First appearance may be at a site of Trauma.
● Nail Involvement ( Pitting )
Clinical manifestation
● Initially the first sign of psoriasis is often red spots on the body
● Dry swollen inflamed patches
● Patched covered with silver white flakes
● Raised and thick skin
28. Pathogenesis-
Tissue injury eg. Trauma
T cells Releases Cytokinines (IL 12,IL 23,Interferon,TNF
KERATINOCYTE PROLIFERATION
EXCESSIVE INFLAMMATION
VESSELS GET DILATED
ERYTHEMA PRODUCED VARIOUS PLASMA PROTEINS AND LEUCOCYTES
AGGREGATES AT THE SITE
Papules , plaques etc formed.
29. Stratum basale
Stratum spinosum
Stratum lucidium
Stratum Corneum
Layers of epidermis
Dendrite cells
(Immune cells)
In psoriasis stratum basale layer becomes
thin and the other layers are thickened
30. Keratinocytes defect-
● Keratin production increased.
● Keratinocytes. Retain nuclei (parakeratosis)
● Stratum basale cells become weak and the cells
of other layers of epidermis get thickened.
● Stratum corneum cells do not adhere properly
due to which a Scaly appearance is formed.
● If the scales picked of localized spots of bleeding
are seen called Auspitz sign.
31. Types of Psoriasis-
1. Chronic plaque Psoriasis-
Common type of Psoriasis
● Character - Pinkish red scaly plaques with silver
scale
● Site - Extensor surfaces knees, elbow etc.
● Lesions - Itchy
33. ● Occur in later life.
● Character - Well demarcated , red glazed plaques
confined to flexures - groin,natal cleft,
submammary area.
● No scaling.
2. Flexural Psoriasis-
35. 3. Guttate Psoriasis-
● ‘Raindrop like’ psoriasis
● Seen in children and young adults.
● Character - Very small circular or oval plaques
appears over trunk.
● Two weeks after a Streptococcal sore throat.
37. 4. Pustular Psoriasis-
● Von zumbush psoriasis.
● Associated with Malaise,Pyrexia,and circulatory
disturbances.
● Palmoplantar psoriasis.
● Pustules are not infected but are sterile collection
of inflammatory cells.
39. ● Most severe type.
● Widespread intense inflammation of the skin.
● medical emergency that may cause acute skin failure
● erythema with or without scaling involving >90% of the
body surface due to excessive cutaneous heat loss, and
haemodynamic upset
● characterised by hypotension and tachycardia.
5.Erythrodermic Psoriasis-
41. ● Varies from minor scaling with erythema to thick
hyperkeratotic plaques.
● May extend beyond hair line.
● Patient scratching may produce asymmetrical plaques.
6. Scalp Psoriasis-
43. Diagnosis
● Based on the distribution of skin damage.
● Tissue biopsy for confirm diagnosis classic
changes in epidermal layer are observed
Complications-
● Nails pitting - 50% of pt develop nail changes.
● Psoriatic arthritis - 5-10% develop Psoriatic
Arthritis.
44. Treatment -
● Moisturizer and Emollients - clear plaque and
minimize itchiness
● Topical therapies - Mild to moderate steroids
,Vitamin D analogies etc
● Cytokine modulators
● Monitoring for toxicity systemic therapy I.e
Methotrexate
● There is no cure for this disease only
suppression is possible.
