17. Acute and Emergency Dermatology Flashcards
What is urticaria and its presentation
Ae = idiopathic, food (nuts, sesame seeds, shellfish, dairy), drugs, insect bites, latex, viral or parasitic infections, autoimmune, hereditary
Path = local increase in cap/venule permeability, superficial dermis
S+S = itchy erythematous rash that comprises of well defined papules and plaques with a smooth surface (wheals)
Ix = skinprick testsand radioallergosorbent tests (RAST) if a drug/food allergy suspected
Mx = anti-histamine, corticosteroids, adrenaline (anaphylaxis)
Outline Stevens-Johnson syndrome
Ae = drugs (cotrimoxazole, penicillin, lamotrigine, allopurinol) or combination with infection
S+S = mucocutaneous necrosis with at least 2 mucosal sites involved, skin involvement <10%
Ix = histopathology (ep necrosis with few inflam cells)
Mx = early recognition, call for help, supportive care to maintain haemodynamic equilibrium
Describe toxic epidermal necrolysis (TEN) spectrum
Ae = drug induced, infection, malignancy, vaccinations
S+S = extensive skin and mucosal necrosis accompanied by systemic toxicity, resulting in possible sepsis/death
Ix = histopathology full thickness ep necrosis with subepidermal detachment
Mx = early recognition, call for help, supportive care to maintain haemodynamic equilibrium, silicone coated dressing, IV Ig (inhib apoptosis)
What is Erythroderma?
Exfoliative dermatitis, involving >90% surface (mortality 20-40%)
Ae = eczema, psoriasis, lymphoma, drugs (sulphonylureas, penicillin, allopurinol), idiopathic, GvHD, HIV
S+S = inflamed, oedematous, scaly, systemically unwell with lymphadenopathy, malaise
Mx = Tx cause, fluid-balance, warmth, emollients, wet-wraps, topical steroids, consider biopsy/swab/culture, Abx, sedative antihistamine
Comp = sec infection, fluid loss, electrolyte imbalance, hypothermia, high-output cardiac failure, cap leak syndrome, hypoalbuminaemia
Outline necrotising fasciitis
Rapidly spreading infection of the deep fascia with sec tissue necrosis - mortality up to 76%
Ae = group A haemolytic strep, mixture of anaerobic and aerobic bact
RF = abdo surgery, DM, malignancy
S+S = severe pain, erythematous, blistering, necrotic skin, fever, tachycardia, crepitus (subcut emphysema)
Mx = urgent referral for extensive surgical debridement, IV Abx
What is eczema herpeticum
Sec infection of atopic eczema
Ae = herpes simplex virus (HSV)
S+S = extensive crusted papules, blisters, erosions, fever malaise
Ix = viral/bacterial swabs
Mx = Aciclovir, IV Abx for sec bacterial infection, IV fluids, topical emollients and steroids
What conditions can cause blistering and how should this be Mx?
Path = desmosomes are attacked, layers of skin separate and the clinical picture resembles a blister
Ae =
- Bullous pemphigoid (AutoAb against T17 collagen - TRUNK/LIMBS)
- Dermatitis herpetiformis (AutoAb against t-TG - ELBOWS, KNEES, BUTTOCKS, LOWER BACK)
- Pemphigus vulgaris (AutoAb against desmosome - MUCOSAL)
- Inset bites (sterile needle burst, dressing)
Ix = skin swab, skin biopsy, immunofluorescence of IgA deposits in the skin, serology
Mx =
- Corticosteroids
- Immunosuppressants - methotrexate, azathioprine
- Dapsone (Abx) and a gluten-free diet
- Genetic therapy: gene, protein, cell, drug
What is generalised pustular psoriasis
Rare and serious flares of widespread sterile pustules on a background of red and tender skin
Ae = sudden withdrawal of injected/PO corticosteroids, drugs: lithium, aspirin, indomethacin, iodide, some beta-blockers, infection
S+S =
- Initially, the skin becomes dry, fiery red and tender
- Within hours, 2–3 mm pustules appear
- After a day, the small pustules coalesce to form lakes of pus
- These dry out and peel to leave a glazed, smooth surface on which new crops of pustules may appear
- Successive crops of pustules may appear and erupt every few days or weeks
Ix = superficial (subcorneal) pustules and neutrophilic infiltration on histopathology
Mx = prevent fluid loss, stabilise body temp, correct electrolyte abnormities, topical compresses using emollients and low potency topical steroid creams, Abx
What is staph scaled skin syndrome, its presentation and a DDx?
Staph (coag +ve) produces an exfoliative toxin that causes the outer layers of skin to blister and peel, as if they’ve been doused with a hot liquid
Most common in children under 6
S+S = fever, irritability, widespread erythema, within 24-48h fluid-filled blisters form; rupture easily, leaving an area that looks like a burn, tissue paper-like wrinkling of the skin, Nikolsky sign (top layers of the skin slip away)
Mx = Abx, analgesia
DDx = drug hypersensitivity, viral exanthemas, scarlet fever, thermal burns, epidermolysis bullosa, toxic epidermal necrolysis
Outline erythema multiforme
Path = hypersensitivity reaction, triggered by infections or drugs
Ae = HSV, barbituates, NSAIDs, penicillin, nitrofurantoin
S+S = skin eruption characterised by a typical target lesion, may be mucous membrane involvement
Mx = acute, self-limiting
