Cutaneous drug eruptions Flashcards
Describe each type of immunologically mediated reaction (types 1-4)
1- IgE mediated, acquired allergy e.g. anaphylactic reactions, urticaria
2-IgG cytotoxic mediated, e.g. pemphigus and pemphigoid
3- IgM immune complex mediated e.g. purpura/rash
4- T helper cell mediated, delayed hypersensitivity e.g. erythema
non-immunological reactions (7)
- Eczema
- Drug induced alopecia
- Phototoxicity
- Skin erosion/ atrophy
- psoriasis
- pigmentation
- Cheilitis/ xerosis
Presentation of Drug eruption? (6)
- Rash: exanthematous, morbilliform (measles like), maculopapular
- Urticarial
- Papulosquamous, pustular, bullous
- pigmentation
- itch or pain
- photosensitivity
Most common type of drug reaction? type of hypersensitivity? presentation? (2) indications of severe reaction? (10) Associated drugs (7)
- Exanthematous eruptions
- delayed type 4, T cell mediated
- symmetrical rash, not on mucous membranes
-face and mucous membranes involved facial oedema and erhythema fever >38.5 blisters/purpura/necrosis lymphadenopathy/arthralgia SOB/wheeze
-Penicillins sulphonamide antibiotics erythromycin/streptomycin Allopurinol NSAIDs chloramphenicol
Urticarial drug reactions
-immune reaction (2)
-IgE mediated, type 1 on re-exposure OR direct release of inflammatory mediators from mast cells on first exposure
Pustular/bullous drug eruptions
- drugs causing acne?
- AGEP, describe, causes
- causes of drug induced bullous pemphigoid
-Glucocorticoids, Androgens, lithium, isoniazide, phenytoin
-acute generalised exanthematous pustulosis
sheets of extensive pustules
antibiotics, CC blockers
-ACE i, Penicillin, furosemide
Fixed drug eruptions
- appearance
- distribution
- associated drugs
-well demarcated, round/ovoid plaques
red and painful
eczematous lesions, papulues, vesicles or urticaria
- hand, genitalia, lips
- tetracycline, doxycycline, paracetamol, NSAIDs, Carbamazepine
severe cutaneous adverse reactions, what are: SJS TEN DRESS AGEP
Stevens-Johnson syndrome
Toxic epidermal necrolysis
Drug reaction with eosinophilia & systemic symptoms
acute generalised exanthematous pustulosis
photo toxic drug reactions
- acute presentation
- chronic presentation
- skin toxicity, systemic toxicity, photodegredation
- pigmentation, photocarcinogens, photo-aging
Cutaneous Phototoxicity patterns, describe the photo toxic reaction to the drugs below: Amioderone Thiazides Calcium channel antagonists psoralen + UV naladixic acid
- immediate prickling with delayed erythema
- exaggerated sunburn
- exposed telangectasia
- delayed (3-5 days) erythema and pigmentation
- increased skin fragility
drugs associated with a photo toxic reaction? (10)
Antibiotics thiazide diuretics NSAIDs Psoralens BRAF inhibitors Antifungals immunosuppressants
investigations in suspected cutaneous drug eruption? (3)
NORMALLY ONLY NEED HX AND EXAM
phototesting
biopsies (look for eosinophils and necrosis)
skin prick/intradermal tests
