Chronically itchy skin can take not only a physical toll but a psychological one as well, a new study suggests.

Research has linked various skin conditions, such as severe acne, psoriasis and eczema, to higher risks of depression, anxiety and stress in some individuals. But it has not been clear whether chronic itchiness — a common symptom of skin disorders — can cause its own distress.

The new study, of more than 2,200 Japanese adults age 18 and up, found that 3 percent complained of chronically itchy skin, also known as pruritus. And the more severe the problem, the more likely they were to score high on a measure of psychological stress.

The findings suggest that the symptom itself, and not just the disorders it marks, can take an emotional toll, according to the researchers, led by Dr. Yosuke Yamamoto of Kyoto University in Japan.

They report the results in the latest issue of Archives of Dermatology.

The study included 2,224 Japanese adults who kept health diaries over one month and completed a standard questionnaire called the Perceived Stress Scale — which measures, for instance, how often a person has felt "nervous" or "stressed" in the past month.

Participants used the diaries to record the presence and severity of various symptoms, including itchiness.

Overall, Yamamoto's team found, participants with itchy skin had a higher average score on the stress scale than other participants did. And the more frequent the symptom, the higher the scores.

The link between itchiness and stress was also seen among participants who had more than two health complaints. This, according to the researchers, suggests that itchiness itself has psychological effects independent of other health problems.

A number of skin conditions — including eczema, recurrent hives and psoriasis — are marked by sometimes intensely itchy skin. The current findings suggest that if the symptom is not well-controlled, it can be a source of psychological, as well as physical, hardship, according to the researchers.

They point out that the questionnaire they used in the study cannot diagnose clinical depression or other mental health disorders. But people's scores do serve as an indicator of general psychological distress.

In turn, the researchers note, chronic stress may affect the immune, hormonal and cardiovascular systems, potentially affecting long-term physical health.

SOURCE: Archives of Dermatology, December 2009.