The dermal type of erythema multiforme: a rare variant of Stevens-Johnson syndrome or cases of clinical misclassification?
Hering O, Mockenhaupt M, Rzany B, Schröder W, Schöpf E.
Since 01.04.90 the Dokumentationszentrum schwerer Hautreaktionen (dZh) in Freiburg has registered cases of severe skin reactions like erythema exsudativum multiforme majus, Stevens-Johnson syndrome and toxic epidermal necrolysis in Germany. With the largest study so far of histological slides from patients included in this registry we were able to show that the epidermal type of erythema multiforme described by Orfanos et al. is the histopathological correlated of these severe skin reactions. Except two biopsies all of the specimens taken from the registered patients showed histological characteristics of this type of erythema multiforme. These two cases are now reported. Clinical data and photographic documentation did not prove authentic erythema multiforme. The lesions of both patients were described as atypical macules and papules; mucosal sites were only locally involved. Biopsies taken from the patients had the characteristics of the dermal type of erythema multiforme (Orfanos et al.). We conclude that histomorphological characteristics of the dermal type, in addition to an atypical clinical course, favour another diagnosis, such as multiforme-like eruption.