Key Point:

Seasonal allergic rhinitis may cause daytime sleepiness through mechanisms other than impaired nocturnal sleep.

MANNHEIM, GERMANY—Patients with seasonal allergic rhinitis often complain of daytime sleepiness, as well as impaired quality of life. The daytime sleepiness has been attributed to disrupted sleep patterns and/or antihistamine use, but new evidence suggests that this may not be the case. Rather, daytime sleepiness may be related to the allergies themselves.[1]

Boris A. Stuck, MD, and colleagues assessed the impact of seasonal allergic rhinitis on sleep patterns, daytime sleepiness, and quality of life among 25 allergy patients and 25 controls. According to Dr. Stuck, who is with the Department of Otorhinolaryngology, Head and Neck Surgery at the University Hospital Mannheim in Germany, their findings indicate that “daytime sleepiness is a common and relevant side effect of allergic rhinitis, but it does not seem to be due to an impairment of sleep.”

SLEEPINESS RELATED TO ALLERGIES, NOT SLEEP PATTERNS

Because most of the patients in this study were allergic to both grass and tree pollen, the investigators assessed them—and the controls—before and in the middle of the pollen season. During the study, no subject was allowed to use antiallergy medications or other drugs that might affect sleep or daytime performance. Allergy symptoms, daytime sleepiness, and quality of life were assessed with questionnaires, and all subjects underwent polysomnography.

Among the allergy patients, symptom scores jumped from 1.08 at baseline to 21.3 during pollen season. Daytime sleepiness scores rose markedly as well (from a mean of 6.8 to 8.2), and there was a concomitant decrease in quality of life in these patients. These effects were most pronounced in the patients with moderate or severe allergies. None of the scores changed in the control group.

DISTURBED SLEEP NOT TO BLAME

Polysomnographic data revealed only minimal and inconclusive changes in sleep parameters, such as rapid eye movement sleep, snoring time, and respiratory events. The absence of clinically relevant differences in sleep parameters suggests that daytime sleepiness results from allergic rhinitis itself and not from a disruption of sleep patterns.

If a disruption in sleep patterns cannot explain the daytime sleepiness, what can? “An impairment of daytime performance (including daytime sleepiness) is a common side effect of inflammatory processes such as influenza, common cold, or bacterial infection,” explained Dr. Stuck. It is therefore not surprising that it would also result from moderate or severe allergies. “We suspect that the inflammatory reaction leads to a release of cytokines, which may affect daytime performance,” he speculated.

Although his study involved young, healthy participants, Dr. Stuck believes that allergy-related daytime sleepiness “may be more pronounced in elderly patients and in those with comorbidities, especially sleep disorders.” Because daytime sleepiness may impair quality of life in any patient with allergies, proper treatment is imperative. “Clinicians should outline the relevant side effects of allergic rhinitis to their patients and stress the necessity of medical treatment,” he concluded.

—Tamara Gibb