Background Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe cutaneous adverse reactions with high morbidity and mortality. Some expressions of lupus erythematosus (LE) may cause enormous difficulties in differentiating them from SJS and TEN by showing large areas of sheet-like epidermal necrosis.
Objective To evaluate clinically and histopathologically probable or definite cases of SJS/TEN with a history of systemic or other LE [(S)LE].
Methods This was a retrospective analysis of validated cases of SJS/TEN with a history of (S)LE, based on a large population-based national registry.
Results Among 1366 patients with SJS/TEN, 17 with a sufficiently documented history of (S)LE and representative histological material could be identified, suggesting a considerable over-representation of LE in patients with SJS/TEN. Eight of these showed clinically and/or histopathologically some LE-characteristic features interfering with the diagnosis of SJS/TEN. Differentiation could be elaborated on clinical and histopathological grounds: four patients were classified as SJS/TEN with a preceding (S)LE exacerbation and/or LE-typical histopathological features, and four as ‘TEN-like’ (S)LE.
Conclusion Most patients with SJS/TEN and a history of (S)LE demonstrate clinical and histopathological properties allowing clear differentiation. However, occasionally acute cutaneous manifestations of (S)LE and SJS/TEN can be phenotypically similar, caused by extensive epidermal necrosis. Although no feature by itself is conclusive, a combination of recent (S)LE exacerbation, evident photodistribution, annular lesions and absent or only mild focal erosive mucosal involvement may favour LE over SJS/TEN clinically. Histopathologically, in particular, junctional vacuolar alteration, and the presence of solitary necrotic keratinocytes at lower epidermal levels, combined with moderate to dense periadnexal and perivascular lymphocytic infiltrates with a variable presence of melanophages, and mucin point to a LE-related origin.