Intradermal deposits of uric acid crystals may be small and discrete, resembling other milia.
The patient presents with small (1 to 3 mm) whitish, creamy or yellowish-white skin lesions which may show an erythematous base. These may or may not be located in periarticular areas.
The findings may be alone or in combination with tophaceous gout or gouty arthritis. The presence of other forms of gout simplifies the diagnosis (and their absence complicates).
The serum urate concentration may be normal or elevated.
Biopsy of the lesion shows an amorphous crystalline material in the dermis or subcutaneous fat with a chronic inflammatory response which may include a foreign-body giant cells.
Demonstration of negative birefringence in the intradermal deposits may or may not be possible in routine sections since tissue processing may dissolve the urates. The deposits may be too small to scrape for crystals. A repeat biopsy with special processing may be necessary.
The diagnosis requires exclusion of other explanation such as intradermal drug injection.
The lesions disappear if the patient is adequately treated for gout.
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