Immune-complex-mediated hypersensitivity disorder. It ranges from mild to severe forms, part of a spectrum that includes Toxic Epidermal Necrolysis (TEN) at its most severe end
Aetiology
Predominant cause of SJS is adverse drug reactions, most commonly from sulfonamides, beta-lactams (penicillins and cephalosporins), antiepileptics, allopurinol, and NSAIDs
Infectious agents, particularly viral pathogens like herpes simplex virus, Epstein-Barr virus, HIV, influenza, and hepatitis, can also trigger SJS
Bacterial and fungal infections are much less common cause
Clinical features
SJS often presents within a week of medication intake, initially resembling an upper respiratory tract infection with symptoms such as cough, cold, fever, and sore throat
Erythematous macules, later becoming target-shaped, appear after a few days
Flaccid blisters develop and the Nikolsky sign is positive
SJS affects less than 10% of the body surface, in contrast to TEN, which involves more than 30% of the skin
Mucosal ulceration is seen in at least two of the following: conjunctiva, mouth, urethra, pharynx, or gastrointestinal tract
Investigations
Predominantly clinical diagnosis
Skin biopsy: can support diagnosis
Necrotic keratinocytes and a sparse lymphocytic infiltrate
Management
Largely supportive, focusing on skin care and prevention of ocular complications through timely ophthalmology referrals
Patients may require hospitalization for fluid and electrolyte management, pain control, and potential treatment of secondary infections
Prognosis
SJS has a 10% mortality rate, primarily due to dehydration, infection, or disseminated intravascular coagulation