Asthma: An Unrecognized Risk Factor for Shingles

Herpes zoster, also known as shingles, is a painful rash caused by a reactivation of the varicella-zoster virus, also called the chickenpox virus.

Risk for shingles increases after age 50, and about 30% of US adults who live to age 80 develop it. Only 10% of patients with herpes zoster are significantly immunocompromised, so other factors must influence the risk of virus reactivation.

A study published the Journal of Allergy and Clinical Immunology identified asthma as one such risk factor for shingles in adults.

The authors analyzed medical records over a 22-month study period, identifying 371 cases of herpes zoster in residents of Olmstead County, Minnesota, who were aged 50 years and older.

Birthday- and sex-matched control subjects with no history of herpes zoster comprised the 742-subject control group.

Almost one-quarter (23%) of herpes zoster patients and 15% of control subjects had a history of asthma. This significant association remained after controlling for confounding factors.

The researchers concluded that a history of asthma might increase the risk of developing herpes zoster by about 10%. In their study, both active and inactive asthma increased the risk of shingles, and asthma medications and control status did not modify the level of risk.

While the mechanism is still uncertain, the researchers hypothesized that asthma may suppress cell-mediated immunity, increasing the risk of developing herpes zoster.

Atopic dermatitis was also associated with an increased risk of shingles. When the researchers controlled for atopic dermatitis, asthma was determined to be an independent risk factor for herpes zoster.

The herpes zoster vaccine is approved in the United States for patients aged 50 years and older, but the US Centers for Disease Control and Prevention recommends routine vaccination starting at age 60, since efficacy may wane within 5 years. Use of the vaccine between ages 50 and 59 is based on patient-specific assessment of risks and benefits.

The study authors advised health care providers to recognize asthma and atopic dermatitis as potential risk factors for herpes zoster when considering vaccination in patients aged 50 years and older.