We thank Bystryn for indicating the remaining confusion on the nosology of the so-called erythema multiforme spectrum.
According to Bystryn, and most authors, the distinction between erythema multiforme and Stevens-Johnson syndrome is based on the extent of mucous membrane erosions and on systemic symptoms (for some authors) and is not correlated to the cause of the disease. In fact, these signs allow the distinction between erythema multiforme minor and erythema multiforme major.1 The latter has been, until recently, confused with Stevens-Johnson syndrome.1
Our aim was to evaluate another system of classification based mainly on the pattern and distribution of skin lesions.2 Our study demonstrated that cases characterized by acrally distributed typical targets were mainly herpes related, whether mucosal erosions involved one or several sites. On the other hand, cases characterized by widespread flat atypical targets or macules plus blisters were mostly drug induced, whether mucosal erosions involved
Assier H, Bastuji-Garin S, Revuz J, Roujeau J. Erythema Multiforme With Mucous Membrane Involvement and Stevens-Johnson Syndrome Are Clinically Different Disorders-Reply. Arch Dermatol. 1996;132(6):711-712. doi:10.1001/archderm.1996.03890300141024