History
A 34-year-old woman who was 24 weeks pregnant developed sudden-onset sore eyes, mouth and geni-talia associated with blisters on her skin. She was admitted to hospital by the obstetricians who referred her to the on-call dermatologist. The patient was diagnosed with HIV at antenatal screening and had been commenced on HAART (highly active antiretro-viral therapy) – Combivir and nevirapine – 2 weeks ago. Over the last 24 hours she has felt unwell with a fever, malaise, sore throat, gritty eyes and a painful stomatitis. Initially she had a few blisters on her face and upper trunk but over a few hours these spread to involve extensive areas of her trunk and limbs.
Examination
She is unwell and distressed. Her temperature is 38.2 °C, blood pressure 180/100 mmHg and pulse rate 110 beats/ min. There is crusting and bleeding of her lips, her conjunctiva are severely injected and she has inflamed nasal mucosa. The genital region is inflamed and ery thematous. She has numerous flaccid and tense blisters over her face, limbs and trunk with many areas becoming confluent with small areas of complete tissue necrosis and skin loss (Fig. 23.1). More than 30 per cent of her skin surface is affected, Nikolsky’s sign is positive.
Questions
• What is the most likely cause of this patient’s sudden onset skin eruption?
• What is the prognosis for the patient and her baby?
• How would you manage them?
Medicine
This presentation with widespread skin loss is typical of drug-induced toxic epidermal necrolysis (TEN). Nikolsky’s sign is positive when lateral pressure is applied to the skin and the top layer sloughs off, and is found in TEN, Stevens–Johnson syndrome and sta-phylococcal scalded skin syndrome and immuno-bullous diseases. The most likely culprit drug here is the antiretroviral nevarapine. Currently physicians are unable to predict which patients will develop severe drug eruptions; however, they are more common in patients with HIV. The trigger antigen sets off a cascade of cell-mediated immune reac-tions including the activation of cytotoxic lymphocytes and natural killer cells resulting in full-thickness skin necrosis (confirmed on the skin biopsy). TEN is a dermatological emergency. Patients should be managed in the intensive care unit by a multidisciplinary team including a dermatologist. Many patients with TEN require sedation and ventilation. The offending drug should be stopped immediately. Topical 50:50 white soft paraffin with liquid paraffin should be applied hourly to all the skin, topical antibiotics and non-adherent dressings (Jelonet®) should be applied to denuded areas. Patients should be kept in a warm room. Fluid and enteral nutrition are essential to compensate for high insensible fluid losses and high protein demands. The evidence for other proactive interventions are mainly anecdotal: many units will treat patients with a total of 2–4 mg/kg of intravenous immunoglobulin over 4 days and 3 mg/kg per day of ciclosporin. TEN has a reported mortality rate of around 20–40 per cent. The mortality rate for any individual patient can be estimated by calculating their SCORTEN – based on seven crite-ria: 40 years of age, pulse 120 bpm, underlying malignancy, 10 per cent body sur-face involved, urea 10 mmol/L, bicarbonate 20 mmol/L and glucose 14 mmol/L. The higher the number of these criteria the patient has, the worse the prognosis (mortality: 1/7 3 per cent, 2/7 12 per cent, 3/7 35 per cent, 4/7 58 per cent, 5–7/7 90 per cent). This patient had a normal healthy baby delivered at term by caesarean section and was switched to Kaletra, lamivudine and tenofovir.
KEY POINTS
• TEN is a dermatological emergency requiring meticulous skin care and supportive therapy.
• Patients usually require sedation and ventilation on the intensive care unit.
• The patient’s prognosis can be estimated by calculating their SCORTEN.
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