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Psoriasis, acne respond to seasonal variations

Symptoms of psoriasis and acne significantly cleared during the summer and worsened in the winter, according to recently published study results.

Researchers used physician’s global assessment (PGA) scores to determine seasonal variation in psoriasis and acne. The year was divided into three 4-month seasons, and chi-square analyses were used to compare seasonal disease clearing and flares. Data were collected between June 2011 and May 2014 in New England.

The researchers collected PGA scores for 5,468 patients with psoriasis, with 16% seen in the spring, 25% in fall, 31% in winter and 28% in spring. Clearing was seen in 20.4% of patients in summer compared with 15.3% of patients in winter. A chi-square test showed significance when the effectively cleared patients were compared over four seasons. Psoriasis also flared in winter (P < .01). Significant trends of summer clearing (P < .05) and winter flaring (P < .01) were maintained in 3,910 patients with psoriasis seen at least two times over a 3-year interval.

There were PGA scores collected for 9,301 patients with acne, with 18% seen in summer, 25% in fall, 28% in winter and 29% in spring. There was a significant difference of average patient age: 28.2 years in summer and 30 years in winter. There were 17.5% of patients graded effectively clear in fall compared with 13.5% in winter. Acne significantly worsened in winter (P < .01). There was a significant trend of summer clearing (P < .01) and winter worsening (P < .05) in analysis of 6,101 patients seen multiple times.

“Winter flaring of psoriasis may be caused by the season’s cold temperature, darkness and low humidity, which can increase skin permeability, epidermal thickening, and stimulate inflammatory mediator production,” the researchers wrote. “Its summer improvement may be attributed to the sun’s known immunomuodulatory and bactericidal effects. Similarly, acne’s summer/fall improvement may be caused by decreased inflammation from ultraviolet light-induced immune suppression and/or decreasing Langerhans cell reactivity. Providers may consider seasonal adjustment of acne plans as they have traditionally done for psoriasis,” the researchers concluded. – By Bruce Thiel

Disclosure: The researchers report no relevant financial disclosures.