Inflammatory dematoses Flashcards by Georgia Leggett

What is the role of melanin in the skin?

Protect keratinocyte nuclei from damage

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Describe the life cycle of a keratinocyte

Originates in BM
Proliferates
Migrates supradermally, producing keratin
Dead + anucleated by the time they reach stratum corneum

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Recall the general pathophysiology of eczema

Defect in barrier function of skin

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Recall the types of sweat gland, and the type of secretion they produce

Eccrine: watery
Apocrine: viscous

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What are the 2 main components of the matrix in the dermis?

Collagens

GAGs

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Which part of the skin is affected by acne?

Pilosebaceous unit

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Summarise the pathogensis underlying acne

Genetic predisposition + Androgenic stimulation
Sebaceous gland hypertrophy
Accumulation of sebum + keratin: colonised by bacteria
Comedone formation

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What are black and white heads and what is the proper term given to them?

Black head = buildup of sebum + keratin at the infundibulum = open comedone
White head = black head with skin on top = closed comedone

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What are the main areas affected by acne?

Face
Neck
Upper back
Upper chest

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By what other name is eczema known?

Dermatitis

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Which of the common skin conditions are classed as atopic?

Eczema

Acne

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Recall how eczema tends to affect individuals over their lifetime

Tends to start young + go away by adulthood

1st step in atopic march, predisposing to food allergies, asthma + rhinitis

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Why does eczema predispose to other atopic diseases?

Defective barrier function of the skin allows infiltration of other allergens

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Recall 3 things that may enter the body through the skin due to eczema

Allergens
Irritants
Pathogens

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What pathogen can act as a “super antigen”, thereby worsening eczema?

Staphylococcus aureus

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What is the function of the filagrin protein?

Epidermal protein maintaining barrier function

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What is palmar hyperlinearity a sign of?

Filagrin gene mutation

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What are the worst-affected areas by eczema on a baby?

Cheeks
Elbows
Knees

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What are the worst-affected areas by eczema in adults?

Areas of sweating + flexure

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Recall 4 types of eczema

Eczema herpeticum
Seborrheic
Allergic-contact dematitis
Discoid

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What type of skin disease is dandruff?

Mild seborrheic eczema

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Recall the pathogenesis of eczema herpeticum

HSV able to penetrate skin due to defective barrier

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Recall which areas are most commonly affected in severe seborrheic eczema

Nasolabial folds
Eyebrows
Forehead

Describe the pathogenesis of seborrheic eczema

Overgrowth of naturally-occurring yeast on skin + a secondary dermatitis reaction to this

Recall 3 common allergens that can cause Allergic Contact Dermatitis

Cosmetics Eye drops PPD in black henna/ hair dye

Where is the most common site affected by discoid eczema? What is the main cause of discoid eczema?

Legs | Dryness

What is the main treatment for discoid eczema?

Emoliant

Describe 3 characteristics of Psoriasis

Erythematous plaques Well defined Scaley

Recall 4 types of psoriasis

Chronic plaque Guttate Palmoplantar pustulosis Generalised pustular psoriasis

Recall a common comorbidity that presents with psoriasis

Psoriatic arthritis

What triggers are required to cause psoriasis?

``` Multigenic: but requires genetic susceptibility Environmental trigger (infection, stress, drugs) ```

Describe the pathogenesis of psoriasis

T cell activation; Cytokine + TNF-a release Stimulate Hyperkeratosis (thickening of keratin layer) Parakeratosis (Corneocytes don't lose their nuclei) Acanthosis (thickening of the epidermis) Inflammation of epidermis (neutrophils) + dermis (lymphocytes) Local vasodilation

Describe the distribution of psoriasis over the body

Very symmetrical | often affects scalp, face, elbows, groin, axilla

What nail signs are produced by psoriasis?

Oncolysis (nail splitting away from bed) Subungual hyperkeratosis (buildup of debris under nail) Cuticle loss Pitting

Describe the appearance of guttate psoriasis

Small papules | Like little raindrops

Which group is most susceptible to guttate psoriasis? What exacerbates guttate psoriasis?

Young people | Streptococcus sore throat

What is the treatment for guttate psoriasis?

Antibiotics | Topical steroids

Which form of psoriasis is driven by genetics alone?

Palmoplantar pustulosis

Which form of psoriasis will require emergency hospital admission? Describe the presentation of a patient with this

Generalised pustular psoriasis | Widespread pustules covering skin, inflammation, increased HR, febrile

What is bullous pemphigoid?

Autoimmune blistering condition | Split in skin is deep

What are the auto-antibodies directed against in bullous pemphigoid?

Proteins that bind dermis to epidermis

Which group is most susceptible to bullous pemphigoid? and why is there a high mortality rate?

Elderly | Blisters easily become septic

Other than bullous pemphigoid, recall a condition that results from basement membrane breakdown. What is this caused by? What does this cause in babies?

Epidermolysis bullosa Genetic defect in proteins holding basement membrane, epidermis + dermis together Shearing of the skin

What is pemphigus vulgaris?

Autoimmune superficial blistering condition

Recall the 2 most common autoimmune skin conditions and how they can be differentiated

``` Bullous pemphigoiD (DEEP) Pemphigus vulgariS (Superficial) ```

Recall the appearance of pemphigus vulgaris

Superficial blisters that easily break to produce erosions + crusted lesions

In pemphigus vulgaris, what is the auto-Ab directed against?

Desmoglein | = Component of epidermal hemidesmosome

What is the result of auto-Ab binding to desmoglen in PV?

Loss of cell-cell adhesion | Split in epidermis

Describe the structure of the stratum corneum

Corneocytes form "bricks" in barrier of skin Lipids + surface proteins form"cement" Creates barrier

Describe the nature of atopic eczema

Common, relapsing + remitting

What change may occur in chronic eczema?

Lichenification- thickening of skin with accentuated markings Poorly defined

What is seen when eczema occurs all over the body?

Erythroderma

List 5 clinical features of acne

``` Whiteheads Blackheads Papules Pustules Nodules ```

What treatment is used for acne?

``` Topical antibiotics (kill bacteria + anti-inflammatory) Certain contraceptive pills (anti-adrenergic effects) ```

Who is effected more by pemphigus vulgaris and bullous pemphigoid?

PV: Adults aged 30-50 BP: Elderly