Immunologically mediated syndrome. May be idiopathic, but usually pre-cipitated by infection (e.g. mycoplasma, herpes simplex, other viruses) or drugs (e.g. sulfonamides, penicillin).
See b Plate 4.
• Crops of characteristic symmetric ‘target’ lesions develop with pallid or purple centre surrounded by erythematous ring.
• May also be haemorrhagic, red macules or large bullae.
• Lesions last 2–3wks and affect hands, feet, elbows, knees.
• Typically, mucous membrane ulcers occur (buccal, eye, genitalia).
If precipitating infection recurs treat early as tends to cause rash again, e.g.
topical aciclovir for recurrent HSV.
• Fluid maintenance.
• Analgesic mouthwashes.
• Lip emollient ointment.
• Oral antihistamines.
Complete recovery, but may recur.
Severe, and overlapping condition with erythema multiforme except usu-ally drug induced with viral infection rarely implicated.
See b Plate 5.
• Widespread blisters/bullae over erythematous, purple macular, or haemorrhagic skin.
• Mucous membranes often affected with haemorrhagic crusting.
• Rubbing may cause skin separation at epidermodermal junction (= positive Nikolsky sign).
• Also possible fever, arthralgia, myalgia, prostration, renal failure, pneumonitis, conjunctivitis, corneal ulceration, blindness.
• Supportive, as for severe burns (e.g. hydration, airway protection).
• Identify causative antigen and remove/treat.
• Frequent emollient ointment.
• Specialist eye care.
• Systemic corticosteroids or immunoglobulin used in first 2–3 days may be helpful if life-threatening.
Can be life-threatening. Recovery usually occurs in 3–4wks.
Exotoxin-mediated epidermolysis s to Staphylococcus aureus infection (which may be trivial). Occurs in children <5yrs.
• Extensive tender erythema with flaccid superficial blisters/bullae (‘scalded appearance’).
• Erosions and +ve Nikolsky sign.
• Crusting around eyes and mouth, fever.
• Supportive treatment and analgesia.
• IV anti-staphylococcal antibiotics.
• Gentle skin care, emollient ointments.
Rapid recovery without scarring.
Highly contagious Staphylococcus aureus or B-haemolytic streptococcal superficial skin infection. May be p or complicate other skin disease (e.g. HSV infection, eczema, scabies). Risk factors include overcrowding and poor hygiene.
• Superficial, rapidly spreading initially clear blisters that rapidly develop into straw-coloured ‘dirty’ looking lesions with yellow crusting.
• Often starts around nose and face; neonates may develop bullous impetigo.
• Risk of staphylococcal scalded skin syndrome or acute glomerulonephritis (streptococcal).
Skin swabs for bacterial culture and sensitivity.
Rapidly resolves if:
• bathe crusts off using antiseptics (contain infectious bacteria);
• antibiotics (e.g. topical mupirocin 2% ointment or oral flucloxacillin);
• treat any predisposing condition.
Caused by friction, burns, or insect bites. Sterile aspiration of blister within 12hr after appearance, and pressure dressing may be curative.