Dermatitis/ atopic ecema Flashcards
What will be seen histologically in eczema?
Spongiosis (oedema between keratinocytes)
Inflammatory cell infiltrate (acute or chronic lypphocytes and/ or neutrophils
What can be seen in the acute phase of eczema?
Papulovesicular rash Erythematous lesions Oedema Ooze/ scaling and crusting ITCH
What can be seen in the chronic phase of eczema?
Lichenification
Elevated plaques
Increased scaling
ITCH
What are the different types of dermatits?
Contact allergic Contact irritant Atopic Drug-related Photo-induces or photosensitive Lichen simplex Stasis dermatitis
What can be seen in the histology of all dermatitis?
Spongiosis
What can be seen in the histology of drug related dermatitis?
Spoongiosis and eosinophils
What can be seen in the histology of stasis dermatitis?
Spongiosis and extravasation of RBCs
What is contact allergic dermatitis?
In response to chemicals, topical therapies, nickel and plants
What is the immunopathology of contact alllergic dermatitis?
Antigen of skin that passes through the skin surface to be detected by langerhan cells which will then migrate through the lymph to present to naeive T cells
These T cells are now primed and so next time the allergen is present, there will be an amplified response
What is irritant dermatitis?
Non-specific physical irritation rather than a specific allergic reaction
Can be difficult to distinguish from allergic contact dermatitis
What features can be seen in irritant dermatitis?
Erythema, scaling, fissuring, lichenification, nail dystrophy, crusting, erosions
How can atopic eczema be described?
Prutitus Ill-defined erythema and scaling Generalised dry skin Flexural distribution (varies with age) Associated with other atopic diseases: asthma, allergic rhinitis, food allergy
Where is atopic eczema likely to affect on the body?
Knees Ankles Eyes Neck Wrist Elbows Groin area Flexural areas
What does a fissure beneath the ear lobe point to?
Pathognomic of atopic eczema
How will eczema present differently in POC?
Often a papular appearance, often with erythema and scaling but this can be hard to see
What would a papular rash in a caucasion person suggest?
Lichen planus
What are chronic changes in atopic eczema?
Lichenification
Excoriation
Secondary infection
What bacteria is likely to infect eczema?
Staph aureus - likely to produce a golden crust
What is eczema herpeticum?
Herpes simplex virus that spreads all over eczema skin
What does the eczema herpeticum rash look like?
Monomorphic punched-out lesions
How can you treat eczema herpeticum?
Acyclovir
What is the diagnostic criterea for atopic eczema?
Itching plus 3 or more: visible flexural rash, history of flexural rash, personal history of atopy, generally dry skin, onset before age 2
How is eczema treated?
Plenty of emollients
Avoid irritants including shower gels and soaps
Topical steroids
Treat infection
Phototherapy - mainly UVB
Systemic immunosuppressants - cyclosporin, methotrexate or azathioprine
What is the most important gene in control of the skin barrier?
Filaggrin
What is discoid eczema?
Circular, well demarcated lesions of scaly, erythematous skin
What is stasis eczema usually secondary to?
Hydrostatic pressure
Oedema
Red cell extravasation
Where is stasis eczema most likely to occur?
Often occurs around the lateral malleolus as this is an area on the leg of greatest hydrostatic pressure
What are the symptoms of seborrhoeic dermatitis?
Symptoms include red, scaly, greasy, itchy, and inflamed skin
Where does seborrhoeic dermatitis usually occur?
Areas of the skin rich in oil-producing glands are often affected including the scalp, face, and chest
What is pompholyx eczema?
Spongiotic vesicles that occur usually due to an acute eruption of eczema
Characteristially on the lateral aspects of the digits
What causes lichen simplex?
Pathology is scratching
How is lichen simplex treated?
Potent topical steroids
