Eczema/Itchy Skin Flashcards
What are the three main types of eczema?
Atopic dermatitis, contact dermatitis (irritant, allergic), drug induced dermatitis
What is the presentation of eczema?
Symmetric, ill-defined, erythematous, patches or plaques, lichenification, erosions (from scratching)
What is the typical color of eczema?
Light pink, flaming red, may appear purple/brown in darker skin tones
What is lichenification?
Thickening of skin, accentuation of skin lines
What is the distribution of atopic dermatitis in infancy?
Facial (especially around the mouth) and scalp dermatitis
What is the distribution of atopic dermatitis in early childhood?
Extensor surfaces
What is the distribution of atopic dermatitis in older children/young adults?
Flexural surfaces
What is the distribution of atopic dermatitis in adults?
Head, neck, and hand lesions
What causes lichenification in atopic dermatitis?
Scratching/rubbing of chronic lesions causes the accentuation of skin lines
What are the histological features of atopic dermatitis?
spongiosis (fluid between cells)
perivascular infiltrate (eosinophils, lymphocytes)
parakeratosis (scale)
acanthosis (thickening of the epidermis)
What is the diagnosis process for atopic dermatitis?
Diagnostic criteria, biopsy
What gene mutation is associated with skin barrier dysfunction in atopic dermatitis?
A mutation in filaggrin 1, which normally is a major component of skin moisture and barrier functions
What is the mechanism of inflammation in atopic dermatitis?
Th2 cells produce IL-13 and IL-4, which leads to downregulation of filaggrin and barrier disruption
What are the psychosocial effects of atopic dermatitis?
Sleep disturbances, associations with other comorbidities, self-consciousness, mental health issues, social isolation
What is the influence of climate on atopic dermatitis?
Increased eczema prevalence in winter with colder temperatures, low humidity, drier air, less UV exposure
What is the treatment for atopic dermatitis?
Topical agents (corticosteroids, calcineurin inhibitors), systemic agents, light therapy and lasers
What is the mechanism of dupilumab?
It is an IL-4 receptor antagonist (that also blocks IL-13) and treats atopic dermatitis
What is the main difference between irritant and allergic contact dermatitis?
Irritant does not require previous sensitization, allergic does require previous sensitization
What is the mechanism of irritant contact dermatitis?
It is mediated by tumor necrosis alpha and non-specific release of junk from damaged cells
What is the mechanism of allergic contact dermatitis?
Allergens cross skin barrier, binds to langerhans cells, recruitment and expansion of T cell clones that are specific. May also involve IL-9 and IL-17.
What class of drugs is the most implicated in drug-induced eczema?
Calcium channel blockers
