Reticular erythematous mucinosis--a review.

Reticular erythematous mucinosis (REM) is a rare cutaneous condition often referred to as plaque-like mucinosis and midline mucinosis. Although the exact etiology remains undefined, efforts to elucidate pathogenesis, disease associations, and prospective treatment modalities have been encouraging. Induction of the disease has been associated with viral processes, solar irradiation, specific cell lines, and cytokines such as Interleukin (IL)-1β. Clinically, patients typically develop erythematous macules and papules that coalesce into reticulated patterns on the midline of the chest or back. The lesions have a tendency to respond to systemic antimalarial therapy, but novel therapeutic approaches with ultraviolet A1 light (UVA1) and pulse dye laser (PDL) have been promising. Histologically, REM is associated with a mild, predominantly lymphocytic infiltrate with variable deep perivascular extension. Mucin may be seen in the upper and mid dermis and is prominent around the infiltrate and appendages. IgM deposits may be visualized under direct immunoflourescence along the basal layer. Because of the similarities between REM and tumid lupus, the two disease processes have often been grouped together. The remarkable overlap between the two diseases suggests that the two conditions may actually be the same disease.