Eczema Flashcards
What is dermatitis?
Eczema
Acute phase of dermatitis
Papulovesicular (fluid filled vesicles)
Red lesions (erythematous)
Oedema (spongiosis)
Ooze or scaling and crusting
Chronic phase of dermatitis
Thickening (lichenification)
Elevated plaques
Increased scaling
Atopic eczema symptoms
Priuritis leads to sleep disturbance which leads to neurocognitive impairment
Ill defined erythema and scaling
Dry skin (generalised)
Flexural distribution (e.g. where the skin folds)
Associated with atopic diseases such as asthma, allergic rhinitis, food allergy
Chronic changes in atopic eczema
Lichenification (thickening of the skin)
Excoriation (areas where the skin has cleared)
Secondary infection (most commonly staph aureus)
UK diagnosis of atopic eczema
Itching plus 3 or more of: visible flexural rash Personal history of atopy Onset before 2 years History of flexural rash dry skin.
Histological appearence of atopic eczema and in what age group is it most common.
Spongiotic dermatitis
young children, generally before 2
Describe the pathogenesis of contact allergic dermatitis
Langerhans cells recognise the antigen near the surface of the epidermis.
They present in on an MHC class I receptor and travel through the dermis into the lymphatics system
It reaches a lymph node where the antigen is presented to the naive T cells. They proliferate, producing memory T cells that remember the antigen for future and producing cytokines bringing about an inflammatory response.
How do you diagnose contact dermatitis?
Patch testing.
Contact irritant dermatitis
Rather than being a specific reaction, it is a generalised reaction to an irritation of the skin e.g. soap.
Produces same histological appearence as other eczemas.
Treatment of contact irritant dermatitis
Remove irritant
Topical steroids and emollients.
Treatment of atopic eczema
Plenty of emollients- improve barrier function of the skin
Avoid irritants
Topical steroids
Phototherapy- provides immunosuppressive properties and relieves priuritis
Systemic immunosupressants- methotrexate, cyclosporin.
Eczema herpeticum
Infection of the herpes simplex virus.
Not ill defined, erythematous or scaly- shows monomorphic punched out lesions.
Drug related eczema
Can produce same histological appearance. However if eosinophils are in the skin and there is spongy dermatitis then its likely to be drug related.
Photoinduced eczema
Reaction to UV light where the light comes into contact with the skin.
