Dermatitis/ Eczema Flashcards
What is parakeratosis?
Persistence of nuclei in the keratin later
What is acanthosis?
Thickened epidermis…
What is papillomatosis?
Irregular epithelial thickening
What is spongiosis?
Oedema between keratinocytes
What occurs in the acute phase of eczema?
Papulovesicular, red lesions, oedema (spongiosis), ooze or scarring and crusting
What occurs in the chronic phase of eczema?
Thickening (lichenification), elevated plaques, increased scaling
What are the causes of contact allergic dermatitis?
Response to chemicals, topical therapies, …
What is hyperkeratosis?
Increased thickness of keratin layer
What is the immunopathology of contact allergic dermatitis?
Langerhans in epidermis processes antigen (increased immunogenicity). Processed antigen is then presented to Th cells in dermis. Sensitized Th cells migrate into lymphatics, then to regional nodes where Ag presentation is amplified. Subsequent challenge- specific T cells proliferate/migrate to skin, results in dermatitis
How can specific substances causing contact dermatitis be identified?
Patch testing
What is irritant dermatitis?
Non specific physical irritation rather than specific allergic reaction
What is nappy rash?
Irritant contact dermatitis to urine with ulceration
What symptom occurs in atopic eczema which leads to neurocognitive impairment?
Pruritis> sleep disturbance> neurocognitive impairment
What symptoms are associated with atopic eczema?
Pruritis, ill-defined erythema & scaling, generalized dry skin, flexural distribution (varies with age). Associated with other atopic diseases
What chronic changes occur in atopic eczema?
Lichenification, excoriation, 2’ infection
What bacteria does crusting in atopic eczema indicate?
S. aureus
What virus causes eczema herpeticum with infection, and what is it characterized by?
HSV, monomorphic punched out lesions
What is the UK diagnostic criteria for atopic eczema?
Itching plus 3 or more of: visible flexural rash, history of flexural rash, personal history of atopy (or 1’ relative if
What is the treatment of eczema?
Plenty of emollients Avoid irritants including shower gels and soaps Topical steroids Treat infection Phototherapy – mainly UVB Systemic immunosuppressants (Biologic agents)
What is the most important gene in the factors that cause atopic eczema?
Filaggrin
If you see a dermatitis cut off at collar, what is it likely to be?
Photosensitive eczema/chronic actinic dermatitis, or caused by photosensitizing drugs
What is stasis eczema secondary to?
Hydrostatic pressure, oedema, red cell extravasation
What symptom will you commonly see in pompholyx eczema, and often where?
Spongiotic vesicles- often side of fingers
Describe the lesions and locations in psoriasis
Symmetrical, sharply demarcated, scaly, erythematous plaques. Extensors, scalp, sacrum, hands, feet, trunk, nails
Where is acne vulgaris distributed?
Sites with most sebaceous glands- face, upper back, anterior chest
What morphology is noted with acne vulgaris?
Comedones- open (blackhead) and closed (whitehead), pustules, papules, cysts
What secondary features are present in acne vulgaris?
Scars- atrophic, ice-pick, texture changes, hypertrophic
What are the 3 grades of acne, and how are they defined?
Mild- scattered papules and pustules, comedones
Moderate - numerous papules, pustules &
mild atrophic scarring
Severe - as above, cysts, nodules and significant scarring
What is found in rosacea?
Papules, pustules and erythema with no comedones, prominent facial flushing exacerbated by sudden change in temperature , alcohol & spicy food
What is the Nikolsky sign?
Nikolsky sign is a skin finding in which the top layers of the skin slip away from the lower layers when slightly rubbed
When is the Nikolsky sign +ve and -ve?
+ve in pemphigus vulgaris, -ve in bullous pemphigoid
What investigations are required in pemphigus and pemphigoid?
Skin biopsy with direct immunofluorescence, indirect immunofluorescence
What is the treatment of pemphigoid and pemphigus?
Systemic steroids
Other immunosuppressive agents: azathioprine, ciclosporin, mycophenolate
In pemphigoid: tetracycline antibiotics, nicotinamide
Topicals: emollients, topical steroids
