Steven-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN)

These are under an umbrella group of conditions called severe cutaneous adverse reactions (SCARs). SJS and TEN are spectrums of the same pathology in which a disproportional immune response (Type IV delayed hypersensitivity reactions, i.e. reactions initiated by CD8+ T cells and NK cells) causes epidermal necrosis, resulting in blistering and shedding of the top layer of skin. The main difference between the two conditions is that SJS affects < 10% of the body surface area and TEN affects > 10% of the body surface area.

Causes

• Medication - Anti-epileptics, Abx, Allopurinol, NSAIDs

• Infection - HSV, Mycoplasma pneumonia, CMV, HIV

Presentation

Patients usually start with non-specific symptoms of fever, cough, sore throat, sore mouth, sore eyes and itchy skin. This then develops into a purple/red rash that spreads and starts to blister. A few days after the blistering, the skin sheds, leaving raw tissue exposed.

Investigations

• Skin biopsy - Shows a layer of sub-epidermal skin blistering and dead, thickened epithelial tissue

Management

• These are medical emergencies and patients should be admitted to a suitable dermatology or burns unit for treatment

• Good supportive care is essential, including nutritional care, Abx, analgesia and ophthalmology input

• Treatment options include steroids, immunoglobulins, and immunosuppressants

Complications

• Secondary infection - The breaks in the skin can lead to secondary bacterial infection, e.g. cellulitis, sepsis.

• Permanent skin damage - Skin involvement can lead to scarring and damage to skin, hair, nails, lungs and genitals.

• Visual complications - Depending on the severity, eye involvement can range from sore eyes to severe scarring and blindness.