To analyze the clinical features and identify risk factors associated with the development of intradermal urate tophi.
Six patients (5 men and 1 woman, mean age 59.8 yrs) with intradermal tophi were studied between 1987 and 1996.
Intradermal urate crystal deposits appeared as small, superficial, pustule-like, whitish lesions. All patients experienced superimposed inflammatory episodes with increasing pain, swelling, and erythema of the intradermal tophi. In one patient, the lesions were associated with a peculiar skin hyperpigmentation. Five had intermittent liquefaction and ulcerations of the lesions with drainage of white chalky matter from which monosodium urate crystals were recovered. Mean pre-treatment serum urate was 570.6 mumol/l (range 496-720). Risk factors for gout and intradermal tophi included renal failure in all 6, hypertension and chronic diuretic therapy in 4, and one patient each with alcohol abuse, chronic low dose acetylsalicylic acid, myeloma, and a positive family history.
Intradermal urate tophi with superimposed inflammatory episodes, intermittent ulcerations, and possibly pigmentary changes, are rare skin manifestations of chronic tophaceous gout. Renal insufficiency, hypertension, and chronic diuretic use are factors associated with the development of hyperuricemia and gout in these patients.