New York, Dec 29 (IANS): People with asthma may be at increased risk of shingles, a common form of painful skin rash caused by the varicella zoster virus, says a new study.

"The effect of asthma on the risk of infection or immune dysfunction might very well go beyond the airways," said lead author Young Juhn, general academic pediatrician and asthma epidemiologist at the Mayo Clinic Children's Research Centre in Rochester, US.

Medical records for potential patients with shingles, also known as herpes zoster, were reviewed in Olmsted County, Minnesota, where 371 cases with shingles -- age 67 on average -- were identified during the study period and compared against 742 control subjects.

Of the 371 shingles cases, 23 percent (87 individuals) had asthma, compared with 15 percent (114 of 742) from the control group.

The authors found that adults with asthma were at about a 70 percent greater risk of developing shingles, compared to those without asthma.

The researchers also noted that both asthma and atopic dermatitis were found to be independently associated with a higher risk of shingles.

Researchers believe that, because asthma helps suppress adaptive immunity, it may increase the risk of varicella zoster virus reactivation.

"As asthma is an unrecognised risk factor for zoster in adults, consideration should be given to immunising adults aged 50 years and older with asthma or atopic dermatitis as a target group for zoster vaccination," Juhn noted.

The researchers note that neither inhaled corticosteroids nor vaccinations were associated with a higher risk of shingles.

The findings appeared in the Journal of Allergy and Clinical Immunology.