Stevens-Johnson syndrome (SJS)

Stevens-Johnson syndrome (SJS) is a rare but serious condition that affects the skin and mucous membranes, such as the mouth, eyes, and genitals. It usually starts with flu-like symptoms followed by a painful rash that spreads and blisters, causing the top layer of skin to die and peel off. This can lead to large areas of raw, exposed skin that are vulnerable to infection and fluid loss. The condition mainly involves the immune system reacting strongly to certain medications or infections, causing widespread skin damage. Because it affects the skin's protective barrier, it can seriously impact overall health and requires urgent medical attention. The severity and rapid progression make it a medical emergency.

Stevens-Johnson syndrome (SJS) is an acute, severe mucocutaneous reaction characterized by extensive epidermal necrosis and detachment involving less than 10% of the body surface area. It is most commonly triggered by a hypersensitivity reaction to medications such as sulfonamides, anticonvulsants, or allopurinol, or less frequently by infections like Mycoplasma pneumoniae. The pathogenesis involves a cytotoxic T-cell–mediated immune response leading to widespread keratinocyte apoptosis. Clinically, it presents with prodromal fever, malaise, and mucosal erosions followed by painful erythematous macules that progress to blistering and epidermal sloughing. SJS is distinguished from toxic epidermal necrolysis (TEN) by the extent of skin involvement and has significant morbidity due to risk of secondary infections, fluid imbalance, and multi-organ complications. Early recognition and withdrawal of the offending agent are critical for prognosis.