Positive Direct Immunofluorescence in Rowell Syndrome: Further Support for a Subtype of Cutaneous Lupus Erythematosus.

Rowell syndrome (RS) is a rare clinical entity characterized by erythema multiforme (EM)-like lesions and lupus erythematosus (LE). Immunologic findings associated with RS include a speckled antinuclear antibody (ANA) pattern, positive rheumatoid factor (RF), and anti-Ro (SS-A)/anti-La (SS-B) antibodies. While direct immunofluorescence (DIF) positivity is a hallmark of cutaneous LE (CLE), recent diagnostic criteria for RS suggest DIF should be negative, raising debate over whether RS is a distinct disease or a CLE variant. We present the case of a 42-year-old woman with systemic lupus erythematosus (SLE) who developed a diffuse, blistering rash consistent with RS. DIF of lesional skin demonstrated immunoreactivity for IgG, complement C3, and IgM along the basement membrane zone, contradicting the proposed RS criteria. This case reinforces the argument that RS is best classified as a CLE subtype rather than a distinct disease. The patient's clinical, serologic, and histopathologic findings, including DIF positivity, support this classification.