Cutaneous Mucinoses

Abstract

The cutaneous mucinoses are a heterogeneous group of disorders whose main characteristic is abnormal mucin deposition in the skin. The aetiopathogenesis of cutaneous mucinoses is unknown, although cytokines such as tumour necrosis factor α and β, interleukin 1, interleukin 6 and transforming growth factor β and/or polyclonal and monoclonal immunoglobulins and other unidentified factors in the serum of affected patients may induce up‐regulation of glycosaminoglycan synthesis. The cutaneous mucinoses are divided into two categories: (i) primary cutaneous mucinoses in which the mucin deposit is the main histological feature resulting in clinically distinctive lesions; and (ii) secondary mucinoses in which the mucin deposition is only an additional histological epiphenomenon. Primary mucinoses can be divided into dermal and follicular mucinoses. The former includes lichen myxoedematosus, reticular erythematous mucinosis, scleroedema, mucinoses in thyroid disease, papular and nodular mucinosis in connective tissue diseases, self‐healing juvenile cutaneous mucinosis, cutaneous focal mucinosis, digital myxoid cyst; the latter include Pinkus follicular mucinosis and urticaria‐like follicular mucinosis. Associated disorders include paraproteinaemia (scleromyxoedema, scleroedema), diabetes mellitus (scleroedema), hyperthyroidism (pretibial myxoedema), hypothyroidism (generalized myxoedema) and lupus erythematosus, dermatomyositis or scleroderma (papular and nodular mucinosis in connective tissue diseases).

Primary paediatric cutaneous mucinoses

“…Although most of the cases in paediatric patients have shown a benign course, long-term follow-up of children with primary FM is nevertheless warranted. 2…”

“…This is the main histopathological clue resulting in distinctive clinical presentations. 1,2 Mucin is an amorphous, highly hygroscopic substance, made mostly in the skin from hyaluronic acid, which is a normal component of the dermal extracellular matrix. It is usually produced in small quantities by fibroblasts and has important physiological functions such as maintaining the hydrosaline balance of the dermis.…”

Scleredema. A multicentre study of characteristics, comorbidities, course and therapy in 44 patients

“…1). 1 Data collected from all the participating centres included demographics, past history, clinical characteristics, laboratory exams, systemic associations, treatment, response, follow-up and outcome. Treatment data included documentation of therapies used for each patient, including dosage of the medication, number of cycles and side-effects, as available.…”

“…Scleredema (synonym: scleredema adultorum of Buschke) is a rare sclerodermiform fibromucinosis that primarily affects the upper body and is caused by excessive collagen and mucin depositions in the dermis. 1 It is classically divided into three types, based on its association with infection (usually streptococcal), monoclonal gammopathy and diabetes mellitus (scleredema diabeticorum) 2 . Limited data are available regarding its course and prognosis.…”

Generalized follicular mucinosis treated with narrow band ultraviolet B radiation

“…Follicular keratinocytes have been considered to be the source of mucin in FM. It has been proposed that cell-mediated immune mechanisms, including a reaction to persistent antigen, may play a role in the pathogenesis of FM [5]. UVB suppresses Langerhans cells and alters their antigen presenting function.…”