SANTA BARBARA, CALIF. — Severe pruritus may be the first presenting sign of cancer, which most typically turns out to be Hodgkin's disease, Timothy G. Berger, M.D., said at the annual meeting of the California Society of Dermatology and Dermatologic Surgery.
But the question that always arises is when to suspect cancer and not one of the many neuropathic causes of itch on normal-appearing skin.
When do you work up a patient when there's nothing to see? “The reason all of us are totally paranoid is that you can't do a CT scan on every patient with itch,” said Dr. Berger, professor of clinical dermatology at the University of California, San Francisco.
His advice is to treat the patient conservatively, but to schedule repeat visits if traditional therapies fail to relieve long-standing idiopathic itch.
He is most concerned, he said, when the itching is “disproportionately severe.”
In such a case, he orders tests of liver function, iron and lactic hydrogenase levels, and endocrine function.
Dr. Berger described a patient with a history of years of severe itch whose sedimentation rate and lactic hydrogenase levels were normal, but who had a CD4 count of 180 cells/μL despite a negative HIV test.
He referred the patient to an oncologist to evaluate a bulge in the groin that the patient thought was a hernia, but proved to be a low-grade T-cell lymphoma.
When patients are undergoing radiation and chemotherapy treatments for Hodgkin's disease but continue to suffer from severe pruritus, Dr. Berger recommends systemic corticosteroids; cimetidine (200 mg, four times daily); or mirtazapine (7.5–15 mg each night) possibly in combination with paroxetine (20–40 mg each night). Patients with solid tumors can also experience severe pruritus, and his advice is to “pick from the bag” of effective therapies, including paroxetine (5–20 mg nightly), mirtazapine (7.5–15 mg nightly), a combination of paroxetine and mirtazapine, or thalidomide (100 mg nightly).
Pruritus is a problem for a third to half of patients with the myeloproliferative disorder polycythemia vera as well, Dr. Berger said. For the vast majority of patients, the itch associated with this disease is aquagenic, occurring for 5–120 minutes after bathing.
The standard treatment has been aspirin (81–300 mg/day); however, a recent survey of patients suggests that a good second choice is paroxetine (20 mg up to 40 mg/day). Other SSRIs do not have the same antipruritic effect in polycythemia vera patients, he said.