Definition

Both above conditions are severe skin detachment syndromes with mucocutaneous complications.

If skin involvement <10% total body surface area, then it’s called Stevens Johnson’s syndrome and If more than 30%, it’s called toxic epidermal necrolysis

There is detachment of epidermis  at the epidermal-dermal junction, causing  papulomacular rash and bullae

Aetiology

Infections

• Pharyngitis/ Mycoplasma pneumoniae/ Herpes/ Epstein-Barr virus/ Cytomegaloviruses.

Drugs

• Anticonvulsants- like carbamazepine, phenobarbital, phenytoin, valproic acid, lamotrigine

• Antibiotics- like sulfonamides, aminopenicillins, quinolones, cephalosporins

• Antifungals

• Antivirals- like nevirapine, abacavir, telaprevir, aciclovir

• Analgesics- like paracetamol, NSAIDS

• Antimalarials

• Azathioprine/ Sulfasalazine/ Allopurinol/ Retinoids

• Corticosteroids

• Anticancer drugs (e.g., bendamustine, busulfan, chlorambucil

Clinical features

Symptoms progress over time, so initially it may be mild signs.

Sudden rash after a new medicine or trigger

Blisters or macules and flat atypical target lesions

Diffuse erythema

Nikolsky’s sign (epidermal layer detachment when pressure is applied to the affected area)

Fever may be present

Diarrhoea, vomiting

Dysuria, enlarged lymph nodes

Arthralgias, arthritis

Hypotension, Dehydration.

Respiratory distress like swollen oral mucosa, vesicle formation, ulceration, shortness of breath, wheezing.

Ulceration of eyes, lips, mouth, pharynx, oesophagus, gastrointestinal tract, kidneys, liver, anus, genital area.

Laboratory evaluation

Tests include:

• Glucose, phosphate, magnesium, bicarbonate
• Full blood count and blood gas
• Liver function tests
• Renal function tests
• Blood culture
• Skin biopsy- this is definitive test for diagnosis.

Treatment

Assess airway, breathing, and circulation status

Assess the total body surface area involved.

Identify and immediately withdraw the causative agent

Prophylactic anticoagulation

Intravenous fluids ± nutritional support-

• Resuscitation fluids as in burns patients
• Children >14 years old and >40 kg, give 2 to 4 mL lactated Ringer’s solution × kg weight × % TBSA
• Children < 14 years old and < 40 kg, give 3 mL lactated Ringer’s solution × kg weight × % TBSA
• Babies less than 10 kgs, give 5% Dextrose 5% in lactated Ringer’s solution.
• Of the total fluid calculated, give 50% in the first 8 hours and rest over next 16 hours

Proton-pump inhibitors- Omeprazole

Analgesia- Paracetamol or morphine

Daily dressings + topical antibacterial agents like silver sulfadiazine or bacitracin + emollients

Intravenous immunoglobulin- controversial

Physiotherapy