Seasonality of restless legs syndrome: symptom variability in winter and summer times

Hyperhidrosis in sleep disorders - A narrative review of mechanisms and clinical significance

Hyperhidrosis is characterized by excessive sweating beyond thermoregulatory needs that affects patients' quality of life. It results from an excessive stimulation of eccrine sweat glands in the skin by the sympathetic nervous system. Hyperhidrosis may be primary or secondary to an underlying cause. Nocturnal hyperhidrosis is associated with different sleep disorders, such as obstructive sleep apnea, insomnia, restless legs syndrome/periodic limb movement during sleep and narcolepsy. The major cause of the hyperhidrosis is sympathetic overactivity and, in the case of narcolepsy type 1, orexin deficiency may also contribute. In this narrative review, we will provide an outline of the possible mechanisms underlying sudomotor dysfunction and the resulting nocturnal hyperhidrosis in these different sleep disorders and explore its clinical relevance.

The prevalence and associated factors of seasonal exacerbation of subjective symptoms in Japanese patients with restless legs syndrome

OBJECTIVES

To elucidate the prevalence of seasonal exacerbation in patients with restless legs syndrome (RLS) and identify its associated factors.

METHODS

We investigated the presence/absence of seasonal exacerbation of RLS by distributing self-administered questionnaires with an interval of three years. Patients who reported having seasonal exacerbation in both surveys were defined as having seasonal exacerbation. RLS severity was determined using the International Restless Legs Syndrome Rating Scale (IRLS).

RESULTS

Among 180 patients, 89 reported having seasonal exacerbation in the first survey. Among them, only two reported not having seasonal exacerbation in the second survey; thus, 87 (48.3%) patients were considered to have a seasonal exacerbation. Although many of them (68 out of 87, 78.2%) experienced exacerbation in spring or summer, 19 out of 87 (21.8%) reported that their symptoms worsened in fall or winter. All the patients in this study had mild to moderate degrees of RLS severity according to the IRLS score. Multiple logistic regression analyses revealed that having a family history of RLS (p < 0.05) and moderate RLS (p < 0.001) were significantly associated with the presence of seasonal exacerbation.

CONCLUSIONS

This study revealed that approximately half of all RLS patients had seasonal exacerbation of the symptoms and that about 80% of the exacerbation was observed during the spring/summer season. Moreover, seasonal exacerbation is likely to be present even in patients whose symptoms had been improved to moderate severity with pharmacological treatment.

The seasonal pattern of restless legs syndrome in a sample from the Korean Health Insurance Review and Assessment Service national database

STUDY OBJECTIVES

To assess the seasonality of restless legs syndrome (RLS) using data from the Korean national health insurance database.

METHODS

We retrospectively reviewed a randomly selected sample representing 3% of the national health insurance claims database in South Korea. From this sample, we obtained the monthly numbers of patients with RLS and diagnoses from 2009 to 2016, along with prescriptions for monthly dopamine agonists and clonazepam for patients with RLS from 2009 to 2013. Total dopamine agonist and clonazepam doses were converted to levodopa-equivalent doses, and the monthly cumulative prescription dose was calculated. Cosinor analysis was used to evaluate the seasonal pattern of each variable.

RESULTS

This study included 11,466 patients with RLS and their diagnoses and 4,887 prescriptions for dopamine agonists and clonazepam. There were significant seasonal patterns in the numbers of patients with RLS (P < .001) and diagnoses (P < .001), both of which peaked in August. The magnitude of the greatest difference in the number of patients with RLS between August (highest) and February (lowest) was 29.96% (95% confidence interval, 24.03-100.80), and that of the number of RLS diagnoses was 39.56% (95% confidence interval, 31.24-47.89). The cumulative prescription dose of medication showed no significant seasonality.

CONCLUSIONS

Our findings suggest that the prevalence of RLS is seasonally affected, with an increase during summer.