Mucinoses

Presents with generalized symmetric eruption of several waxy firm papules accompanied by induration and thickening of the skin (sclerodermoid) with ↓ mobility; typically involves hands, forearms, face (‘leonine facies’), neck, thighs and upper trunk; associated with monoclonal gamopathy (paraproteinemia) IgG λ (lambda light chain); due to fibroblast proliferation and mucin deposition in dermis; non-cutaneous manifestations include myopathy, arthropathy, neuropathy, dysphagia, lung and renal disease; poor prognosis

Treatment: disappointing; stem cell transplant, oral immunosuppressants (including thalidomide), electron beam therapy; of note, monthly melphalan used in past but associated with ↑ mortality

Lichen myxedematosus
(Papular mucinosis)

Localized form of scleromyxedema (spectrum) with small, flat-topped shiny papules mainly over extensor extremities; does not progress to scleromyxedema but shows little tendency for spontaneous resolution

Treatment: observation or topical corticosteroid

Scleredema
(Scleredema of Buschke)
(Scleredema diabeticorum)

Three forms:

– Infection-related: preceding fever, malaise and infection (typically streptococcal) in children and women; presents with induration of cervicofacial area with extension to proximal extremities and trunk; typically self-limited
– Gammopathy-related: similar to above but with insidious onset and without preceding infection; typically associated with monoclonal gammopathy
– Diabetes-related: subtle onset erythema and induration of neck and back (± peau d’orange appearance) in obese men with IDDM; persistent involvement

All three may have some form of systemic involvement: dysphagia, cardiac abnormalities, serositis

Treatment (for latter two types): phothotherapy, cyclosphosphamide, oral glucocorticoid, cyclosporine

Reticular erythematous mucinosis
(REM)

Erythematous macules and papules in reticulated pattern over midline chest and back; may be induced by UV light

Treatment: antimalarials, sun protection