The differential diagnosis for eruptive xanthoma includes xanthoma disseminatum, non–Langerhans cell histiocytoses (eg, generalized eruptive histiocytosis), and cutaneous mastocytosis.1
Xanthoma disseminatum is an extremely rare, but benign, disorder of non–Langerhans cell origin. The average age of onset is older than 40 years. The rash consists of multiple red-yellow papules and nodules that most commonly present in flexural areas. Forty percent to 60% of patients have mucosal involvement, and rarely the central nervous system is involved.8
Generalized eruptive histiocytosis is another rare non–Langerhans cell histiocytosis that occurs mainly in adults and is characterized by widespread, symmetric, red-brown papules on the trunk, arms, and legs, and rarely the mucous membranes.9
Cutaneous mastocytosis, especially xanthelasmoid mastocytosis, consists of multiple pruritic, yellowish, papular or nodular lesions that may mimic eruptive xanthoma. It occurs mainly in children and rarely in adults.10
Confirming the diagnosis, initiating treatment
The diagnosis of eruptive xanthoma can be confirmed by skin biopsy if other differential diagnoses cannot be ruled out or the lesions do not resolve with treatment. Skin biopsy will reveal lipid-laden macrophages (known as foam cells) deposited in the dermis.7
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