Inflammatory dermatoses Flashcards
What is the biology of acne
a. Disease of pilosebaceous unit of the skin
b. Hyperkeratinisation of epidermis in the infundibulum of hair follicle
c. Accumulation of dead keratinocytes in lumen of hair follicle
d. Overproduction of sebum stimulated by androgens
e. Comedone formation
f. Proliferation of Propionibacteria acnes within pilosebaceous unit
g. Rupture of inflamed pilosebaceous unit with further inflammation of surrounding skin
- What is the clinical manifestation of acne
a. Open and closed comedones (blackheads and whiteheads)
b. Papules
c. Pustules
d. Nodules and scars on face, chest and back
- What is the biology of atopic eczema
a. Defects in the lipids between corneocytes in the stratum corneum
i. Needed for the barrier function
b. Filagrin mutation is common -> dryness of the skin
c. Penetration of allergens, irritants and pathogens + defects in epidermal skin barrier -
i. Langerhan cells -> cd4 -> th2 immune response
ii. Chronic -> cd4 and cd8 -> th1 immune response
What is the clinical manifestation of atopic eczema
a. Palmar hyperlinearity = filagrin gene mutation
b. Areas affected in baby is where they have access to (face, cheeks, elbows, knees)
c. In adults it’s in sweaty areas (fossae)
d. Acute = crusted and very red
e. Chronic = lichenification (accentuation of skin lines, looks thick), not red
- What is seborrheic eczema
a. Not itchy
b. Due to overgrowth of malassezia species of yeast on skin -> associated skin inflammation
c. Distinctive distribution = nasolabial folds, eyebrows, scalp, central chest, axillae, groins
i. Scalp = dandruff
d. Can have triggers (stress, sun, lack of sleep)
What is the biology of psoriasis
a. Inflammatory dermatoses
b. Genetic susceptibility = PSOR1 gene + others
c. T lymphocytes go into dermis and release cytokines such as tnf alpha
d. Epidermis becomes thickened and produce more keratinocytes
e. Neutrophils infiltrate epidermis
f. Lymphocytes infiltrate dermis
- What is the clinical manifestation of psoriasis
a. Salmon pink colored plaques with silvery scales
b. Symmetrical
c. Scalp, face, armpit, trunk, elbows, groin and genital, buttocks, nails, knees
Trigger = stress, drugs, infections
- What are other types of psoriasis
a. Guttate
i. Triggered by strep throat
b. Palmoplantar pustulosis
c. Generalised pustular psoriasis
- What is the biology of bullous pemphigoid
a. IgG autoantibodies to basement membrane antigens BP180 (type 17 collagen) or BP30 resulting in cleavage of skin at the dermoepidermal junction leading to subepidermal blisters
What is the clinical manifestation of bullous pemphigoid
a. Intense pruritus followed by tense blisters on erythematous background of skin or mucous membrances
- What is the biology of pemphigus vulgaris
a. IgG autoantibodies to epidermal cell surface proteins desmogleins 1 and 2 leading to loss of cell-cell adhesion (acantholysis) within epidermis causing flaccid blisters in the skin/mucous membranes
- What is the clinical manifestation of pemphigus vulgaris
a. Flaccid blisters which easily break leaving erosions and crusted lesions
