Break anogenital itch-scratch cycle with sedatives. (Antidepressants Sometimes Needed).

Houston--Sometimes sedatives or antidepressants are needed to break an insidious cycle of itching and scratching before the cause of a patient's anogenital pruritus can be identified.

Scratching at night, even during sleep, is one of the hallmarks of the cycle, so the only way to disrupt it is to prescribe medication that soothes the itching and allows the patient to get a good night's rest, Dr. Peter Lynch said at a conference on vulvovaginal diseases sponsored by Baylor College of Medicine.

The problem begins when a relatively mild itch elicits scratching, which in turn stimulates nerve fibers in the skin that prolong and intensify the itching, which generates more scratching, and so on.

"It's an unending cycle of itching and scratching that the patient cannot stop on her own until pain replaces the itching," said Dr. Lynch, professor emeritus of dermatology at the University of California, Davis.

Often the itching continues after the original cause has resolved. Usually it is especially bad at night, when patients are freed from daytime distractions and social constraints.

The patient may deny or minimize the extent of her scratching out of embarrassment or because she scratches in her sleep--information that you can obtain from her partner.

To prevent nighttime scratching, Dr. Lynch prescribes hydroxyzine or doxepin, starring with a dose of 25 mg taken 2 hours before bedtime to prevent a hangover effect the next morning. The dose of either compound can be gradually increased up to 75 mg if necessary to keep the patient from scratching. For daytime use, selective serotonin reuptake inhibitors provide itch relief without the drowsiness associated with sedatives. Citalopram, fluoxerine, or paroxerine may be prescribed in doses of ...