International journal of dermatology
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A role for histamine in the pathogenesis of uremic pruritus was investigated in maintenance hemodialysis patients. Venous plasma histamine levels, as determined by radioenzymatic assay, were significantly higher (p less than 0.05) in hemodialysis patients with pruritus (368 +/- 103 pg/ml [mean +/- SEM], n = 6) than in those without pruritus (146 +/- 22 pg/ml, n = 5) and in normal controls (142 +/- 16, n = 5). Arteriovenous fistula histamine levels (202 +/- 52 pg/ml, n = 6) were significantly lower (p less than 0.05) than simultaneously drawn venous samples. ⋯ Five of five patients had significant (p less than 0.01) reductions in pruritus, as judged on a six-point pruritus index, after 8 weeks of drug (x = 2.3), as compared to conventional therapy (x = 5.9). Despite these improvements, no significant differences were noted in pre- versus post-drug plasma histamine levels, histaminase activities, or the histamine content per gram of skin biopsy specimen. These data support prior hypotheses that mast cell activation contributes to the pruritus of uremia.