Scleredema — SCE Dermatology MCQ

Correct answer: A — Scleredema diabeticorum (scleredema of Buschke)

The correct answer is A, scleredema diabeticorum (scleredema of Buschke). This man has poorly controlled type 2 diabetes and woody induration extending into the subcutis with peau d'orange skin, the classic clinical picture of scleredema, a cutaneous mucinosis strongly associated with long standing, poorly controlled diabetes (type 3 scleredema). The negative ANA and anti-Scl-70 argue against an autoimmune sclerosing process, and the histology of thickened collagen bundles separated by mucin deposition in the reticular dermis, without significant inflammatory infiltrate or vascular changes, is diagnostic of scleredema rather than the alternatives. Why the other options are wrong: E. Morphoea: presents with localised, often asymmetric, violaceous bordered plaques of sclerosis that progress to ivory coloured atrophic centres, and biopsy shows dermal sclerosis with loss of adnexae rather than prominent interstitial mucin. B. Pretibial myxoedema: occurs in Graves disease, produces waxy, nodular or plaque like thickening confined to the pretibial region with abundant mucin but no thickened collagen bundles, and is linked to thyroid autoimmunity, not diabetes. C. Lipodermatosclerosis: relates to venous insufficiency, causing an inverted champagne bottle deformity with fibrosing panniculitis, not diffuse woody induration with dermal mucin. D. Systemic sclerosis: requires features such as Raynaud phenomenon, sclerodactyly and a positive anti-Scl-70 or ANA; the negative serology here excludes it. Key point: Woody, non-pitting induration of the skin in a poorly controlled diabetic, with dermal mucin between thickened collagen bundles and negative scleroderma serology, points to scleredema diabeticorum, not systemic sclerosis or morphoea.

Reference: Primary Care Dermatology Society (PCDS), Scleroedema clinical guidance, https://www.pcds.org.uk/clinical-guidance/scleroedema