Common Rashes Flashcards
Clinical features of acute eczema
Papulovesicular erythematous lesions
Itch
Ill defined
Oedema
Ooze or scaling and crusting
Histology of acute eczema
Inflammatory infiltrate in the upper dermis
Fluid collections
Clinical presentation of chronic eczema
Lichenification
Elevated plaques
Increased scaling
Excoriation
Secondary infection
Clinical feature of adult eczema
Generalised dryness and itching, hand eczema may be the primary manifestation of
Clinical feature of childhood eczema
Predominantly flexural
Clinical features of infantile eczema
Primarily involves face, scalp, and extensor surfaces of the limbs
Nappy area usually spared
What kind of reaction is contact allergy dermatitis
Type 4 hypersensitivity reaction to an external antigen
Sensitisation stage of contact allergic dermatitis
Generation of memory T cells following exposure to antigen via langerhans cells in the epidermis and MHC-II
Allergic stage of contact allergic dermatitis
Activation of sensitised Th cells in response to antigen causing the release of inflammatory cytokines and cell mediated cytotoxicity
Investigations for contact allergy dermatitis
Patch testing
What happens in patch testing
Allergens prepared into Finn chambers which are applied on the back and removed at 48 hours
What is contact irritant dermatitis
Non-specific physical irritation
What can cause contact irritant dermatitis
Soap
Water
Cleaning products
Nappy rash
Where does contact irritant dermatitis usually present
On the hands
Genetic association with atopic eczema
Mutations in fillagrin gene
Clinical features of atopic eczema
Ill defined erythema and scaling
Itch-scratch cycle
Generalised dry skin
What distribution is seen in atopic eczema
Flexural
Complication of atopic eczema
nodular prurigo
What is nodular prurigo
Itchy nodules or papules on the skin
What is atopic eczema usually associated with
Asthma, allergic rhinitis, food allergy
Diagnostic criteria for atopic eczema
Itching + 3 or more of the following:
Visible flexural rash or history
History of atopy
Generally dry skin
Onset before age of 2
Management of atopic eczema
Targeted blocking of IL4 and IL14
Drug related eczema
Type 1 or 4 hypersensitivity, eosinophils will be present
Photo-induced or photosensitive eczema
Well defined
Patients are often atopic
Reaction to UV light OR secondary to photosensitising drugs
What causes lichen simplex
Physical trauma to skin
What causes stasis dermatitis
Physical trauma to skin caused by increased hydrostatic pressure of the blood (venous insufficiency)
Where is stasis dermatitis seen
Lower legs
What is discoid eczema
Eczema which occurs in well defined circular or oval patches
What is another name for seborrhoeic eczema
Cradle cap
Where does seborrhoeic eczema tend to affect
Nose, eyebrows, ears and scalp
When does dyshidrotic eczema occur
When there is a very sudden acute flare up of eczema and the spongiotic vesicles join together
Clinical presentation of dyshidrotic eczema
Tiny blisters develop in hands and feet
Classically on the sides of fingers
What is another name for dyshidrotic eczema
Pompholyx eczema
General measures for managing eczema
Avoid irritants
Loose cotton clothing
Emollients
Management of mild eczema
Topical steroid
Management of moderate eczema
Moderate topical steroid
Give an example of a moderate topical steroid
Betamethasone valerate 0.025%
Management of severe eczema
Potent topical steroid
Consider occlusive dressings
Treat infection if that’s a factor
Secondary care options for the management of eczema
Phototherapy
Immunosuppression
Biological agents
What is psoriasis
A common chronic inflammatory dermatosis
Genetic links in psoriasis
Associated with HLA genes and PSORS1 locus
When does psoriasis usually present
2 peaks in incidence
20s and 50s