Pruritus is a major disorder among the skin derangements in advanced renal failure. Recent information suggests that interactions between dermal mast cells and distal ends of nonmyelinated C fibers may be important in the precipitation and regulation of the sensory stimuli.Patients having uremic pruritus have been noted to have increased levels of plasma histamine and tryptase as well as increased numbers of dermal mast cells.Cromolyn sodium is a mast cell stabilizing agent that inhibits degranulation of mast cells and the release of histamine, tryptase, and leukotrienes. It is hypothesized that oral cromolyn sodium may attenuate uremic pruritus by decreasing serum tryptase level.

Inclusion Criteria:

• Hemodialysis patients > 18 yo suffering from pruritus for at least 6 weeks, and who have not responded to other drugs
• Willing and able to give informed concent

Exclusion Criteria:

• Known dermatologic, liver, metabolic disease, or any other disease or condition other than ESRD that causes pruritus
• Lactase deficiency