Cutaneous mucinoses

The cutaneous mucinoses are a heterogeneous group of diseases in which mucin accumulates in the skin or within the hair follicle. We divide the cutaneous mucinoses into two groups: the distinctive cutaneous mucinoses in which the mucin deposit is a distinctive histopathologic feature that manifests as a clinically specific lesion, and the diseases associated with histopathologic mucin deposition as an additional finding. This article deals with the clinical and histopathologic features and the treatment of the distinctive cutaneous mucinoses and updates their classification. They may be divided, according to the microscopic location of mucin, into dermal and follicular mucinoses. The former group includes: lichen myxedematosus, acral persistent papular mucinosis, reticular erythematous mucinosis, scleredema, dysthyroidotic mucinoses (i.e. localized myxedema, generalized myxedema, papular mucinoses associated with thyroid diseases), papular and nodular mucinosis associated with lupus erythematosus, self-healing juvenile cutaneous mucinosis, cutaneous mucinosis of the infancy, cutaneous toxic mucinoses (papular mucinosis of the toxic oil syndrome and of eosinophilia myalgia syndrome), neuropathia mucinosa cutanea, cutaneous focal mucinosis, mucous cyst (digital and of the oral mucosa), while the latter group includes Pinkus' follicular mucinosis and urticaria-like follicular mucinosis.