Epidermal Necrolysis is an immune-complex mediated inflammatory condition where the skin is destroyed at the level of the junction between the epidermis and dermis. It is a spectrum that is termed differently depending on the severity. Epidermal necrolysis follows a reaction to a drug and starts within 8 weeks of starting a new medication. Diagnosis is clinical. For treatment, the offending drug is removed, and the wounds are treated as massive burns. Steroids, IV immunoglobulins, and plasmapheresis seem to provide no benefit. Necrolysis lasts 7-10 days, and re-epithelialization occurs over three weeks. Most patients end up in the ICU. Prognosis is determined by the percentage of skin involved. Patients with SCORTEN >3 should be managed in the ICU.
10% of SJS and 30% of TEN cases are fatal. Affects 1-2 million people per year. Affects females more than men. 100 times more common in patients with HIV. There is a genetic predisposition. More than 200 drugs are known to cause epidermal necrolysis. About 20% of cases are due to infection (or rarely vaccination)
SJS-TEN Spectrum
| Steven-Johnson Syndrome (SJS) | Term |
|---|---|
| <10% | Steven-johnson Syndrome (SJS) |
| 10-30% | TEN-SJS Overlap Syndrome |
| >30% | Toxic epidermal necrolysis (TEN) |
SCORTEN illness severity score
| Component | Points |
|---|---|
| Age > 40 | 1 |
| Known malignancy (of any type) | 1 |
| Heart rate >120 bpm | 1 |
| Percentage of skin detachment at presentation >10% | 1 |
| Urea >10 mmol/L | 1 |
| Glucose >14 mmol/L | 1 |
| Bicarb <20 mmom/L | 1 |
Mortality risk based on SCORTEN
| Score | Mortality |
|---|---|
| 0-1 | 3% |
| 2 | 12% |
| 3 | 35% |
| 5 or more | 90% |
- Drugs associated with epidermal necrolysis
- Aromatic anticonvulsants
- Sulfonamides
- Allopurinol
- Oxicams (NSAIDs)
- Nevirapine
- Signs and symptoms
- Macular rash on the face and trunk that spreads rapidly to involve the extremities
- Nikolsky sign (lateral pressure on the skin produces epidermal sloughing)
- Macules become Bullae that burst (leading to sloughing of the epidermis and exposure of the underlying dermis)
- Prodromal symptoms (fever, sore throat, dysphagia, URTI symptoms, conjunctivitis, myalgia, joint pain)
- Mucosal involvement (90% of cases – eyes, mouth, pharynx, esophagus, genitals, respiratory and gastrointestinal tract)
- Investigations
- Serum granulysin: to detect epidermal necrolysis in the first few days, when the character of the rash cannot predict epidermal necrolysis
- Skin biopsy: to confirm the diagnosis
- Full-thickness epidermal necrosis with minimal inflammation
- Negative immunofluorescence (lack of antibody deposition)
- U/E/Cs: assess electrolytes and kidney function
- Complete blood count: assess anemia (common). Neutropenia is a poor prognostic factor
- LFTs: raised in 30% of cases. 10% develop hepatitis
- Proteinuria: occurs in 50% of patients
- Principles of treatment
- Immediately discontinue the inciting drug
- Manage lesions as burns: wound care, surgical debridement of dead tissue
- Treat the underlying infection
- IV fluid therapy to replace electrolytes
- Analgesia
- Anaesthetic mouthwash
- Eye care (ophthalmology assessment, antibiotics, steroid eye drops)
- Acute complications
- Multiple organ failure
- Dehydration
- Malnutrition
- Venous Thromboembolism
- Bowel perforation
- Secondary skin infection and scarring
- Eye complications (uveitis, corneal ulceration)
- Long-term complications
- Hyperhidrosis
- Hair loss
- Heat and cold sensitivity
- Altered skin pigmentation
- Vaginal stenosis and penile scarring
- Urethral and anal strictures
- Sight impairment