Derm 2 - Emergencies and skin infections Flashcards
Urticaria, angioedema and anaphylaxis are examples of which type of hypersensitivity reaction?
Type 1 hypersensitivity reaction - IgE-mediated
List some common triggers of urticaria/angioedema/anaphylaxis:
Foods: Nuts, shellfish, dairy Drugs: Penicillin, contrast media, NSAIDs, morphine, ACEi Insect bites Contact: Latex Autoimmune Hereditary (angioedema)
How does urticaria present?
Itchy wheals
How does angioedema present?
Swelling of dermis, tongue and lips
How does anaphylaxis present?
- Bronchospasm
- Facial/laryngeal oedema
- Hypotension
- Wheeze
- Cyanosis
What is the management of urticaria?
- Trigger avoidance
- Anti-histamines
- Corticosteroids if severe acute
What is the management of angioedema?
- Trigger avoidance
- Corticosteroids
What is the management for anaphylaxis?
- Trigger avoidance
- Adrenaline - 500 ug
- Hydrocortisone - 200 mg
- Chlorphenamine - 10mg
List some causes of erythema nodosum:
- Sarcoidosis
- Strep throat
- TB
- Pregnancy
- Malignancy
- IBD - Crohns/UC
- Chlamydia
- Leprosy
- Drugs: COCP, Sulphonamide abc, NSAIDs
Describe the lesion seen in erythema nodosum:
Discrete tender nodules on the shins/ankles
What is Stevens-Johnson syndrome?
Acute skin reaction (type 4 hypersensitivity reaction) causing mucocutaneous necrosis, often triggered by drugs.
- Blistering skin
- Mouth ulcers
- Sore, ulcerating eyes
- Diarrhoea
- Cough
What is Toxic Epidermal Necrosis?
Acute widespread skin and mucosal necrosis in reaction to a drug - type 4 hypersensitivity reaction.
>30% mortality
Name the serious complication of atopic eczema, characterised by extensive crusty papule, blisters and erosions:
Eczema herpeticum
What is the infective agent causing eczema herpeticum? What is the treatment?
- Herpes simplex virus
- Aciclovir
Differentiate between cellulitis and erysipelas:
Cellulitis = bacterial infection of deep subcutaneous tissue Erysipelas = Bacterial infection of dermis and upper subcutaneous tissue, which has a well-defined, red raised border.
What are the common infective agents causing cellulitis and erysipelas?
- Strep pyogenes
- Staph aureus
Which antibiotics should be given for cellulitis/erysipelas?
- Flucloxacillin or Benzylpenillin
What is tinea corporis?
Tinea infection of trunk and limbs.
- Itchy, circular lesions, with clearly defined, raised scaly edge
What is tinea cruris?
Tinea infection of groin and natal cleft
- Itchy
What is tinea pedis?
Athlete’s foot = moist scaling and fissuring in toewebs
What is tinea manuum?
Tinea infection of the hand
Scaling and dryness in palmar creases
What is tinea capitis?
Patches on scalp of broken hair, scaling and inflammation
What is tinea unguium?
Tinea infection of nail
- Yellow, thickened, crumbly nail
What is the treatment for a tinea infection?
- Correct predisposing factors ie moist environment
- Topical antifungal - Terbinafine
- Oral antifungal - Itraconazole
Why shouldn’t topical steroids be used on tinea infections?
Lead to tinea incognito
What is pityriasis versicolor?
Scaly brown patches on upper trunk which fail to tan on sun exposure
Hyperpigmentation and hyperkeratosis of skin folds…
Acanthosis nigricans
What conditions is acanthosis nigricans associated with?
Gastric cancer Insulin resistance: - Hyperinsulinaemia - Cushing's - Acromegaly - PCOS
What is the infective agent in scabies?
Sarcoptes scabiei
What are the presenting features of scabies?
Extremely itchy rash, widespread tiny red spots and scratches, particularly in skin folds
May resemble eczema
What is Permethrin used to treat?
Scabies infestation
What is the management of scabies?
- Topical insecticide: Permethrin 5%
- Advise all close contacts to get tx
- Wash and dry bedding, towels and clothes >60’C
