reticular erythematous mucinosis reticular erythematous mucinosis reticular erythematous mucinosis (rem) is a skin condition caused by fibroblasts producing abnormally large amounts of mucopolysaccharides. it is a disease that tends to affect women in the third and fourth decades of life.: 187 reticular erythematous mucinosisother namesmidline mucinosis, plaque-like cutaneous mucinosis, and rem syndromespecialtydermatology