Scleromyxoedema — SCE Dermatology MCQ

Correct answer: B — Intravenous immunoglobulin (IVIG)

The correct answer is B, intravenous immunoglobulin (IVIG). Scleromyxoedema (Arndt-Gottron syndrome) is a rare primary cutaneous mucinosis defined by the triad in the stem: generalised sclerodermoid papular eruption, IgG-lambda paraprotein, and dermal mucin with fibroblast proliferation on histology. There is no licensed disease-modifying agent, but high-dose IVIG has the most consistent evidence of cutaneous and systemic improvement and is regarded as first-line systemic therapy, reserving agents such as thalidomide or autologous stem cell transplantation for refractory cases. IVIG also has a favourable side-effect profile compared with prolonged high-dose steroids in a disease that already carries paraprotein-related and cardiac risk. Its benefit is thought to relate to immunomodulation of the underlying plasma cell clone and reduction in circulating factors driving fibroblast mucin production. Why the other options are wrong: D. Oral Prednisolone alone: Corticosteroid monotherapy gives inconsistent responses, relapse is common on tapering, and prolonged use adds metabolic and infective risk without addressing the paraprotein-driven process; steroids are used adjunctively, not as first-line monotherapy. A. Oral Hydroxychloroquine: This has no established efficacy in scleromyxoedema and is not part of recognised treatment pathways for this condition; it is reserved for other connective tissue and cutaneous lupus disorders. E. Oral Methotrexate: Methotrexate lacks robust evidence in scleromyxoedema and is not recommended first-line; case reports are sparse and inconsistent compared with the IVIG evidence base. C. Topical corticosteroids alone: Topical therapy cannot address the systemic paraprotein-driven fibroblast proliferation and mucin deposition, and does not modify systemic or cardiac/neurological complications of scleromyxoedema. Key point: In scleromyxoedema, the combination of paraproteinaemia, sclerodermoid papules and dermal mucin/fibroblast proliferation should trigger IVIG as first-line systemic treatment, not steroids or topical measures.

Reference: Hoffmann JHO, Enk AH. Scleromyxedema. JDDG: Journal der Deutschen Dermatologischen Gesellschaft 2020;18:1449-1467 (European S1 guideline consensus, endorsed for use in UK dermatology practice, states high-dose IVIG is first-line treatment of scleromyxoedema). https://doi.org/10.1111/ddg.14319