Seasonality in psoriasis is evident in internet search data  for ‘psoriasis’ topics that shows peaks in later winter/early spring and troughs in later summer/early autumn.

The data is consistent with clinical and epidemiological evidence that the disease worsens in winter and improves in summer, say researchers.

Google Trends data on psoriasis searches conducted between 2004 and 2018 showed a significant worldwide pattern of seasonal variation evident in both southern and northern hemisphere countries.

The study found the number of psoriasis-related searches declined from 2004 to 2010 but has since steadily increased.

Peak interest each year was in July/August in southern hemisphere countries of Australia and New Zealand and in February/March in the northern hemisphere countries of Canada, Ireland, the UK and US.

“…and troughs of psoriasis-related RSV [relative search volume] occurred in late summer/early autumn months (August/September for the four northern hemisphere countries and January/February for the two southern hemisphere countries).”

The researchers said the main reasons why adults search for medical information is to gather disease-related information before seeing a physician or to supplement information provided by the physician.

“Medications, symptoms and concomitant diseases of psoriasis were the fundamental concerns of those who searched for psoriasis-related information,” the study said.

The top three Google search topics related to psoriasis were calcipotriol/betamethasone dipropionate, ustekinumab and apremilast drug.

Other popular search topics were shampoo, eczema, guttate psoriasis, seborrhoeic dermatitis, dermatitis, psoriatic arthritis disease or medical treatment, atopic dermatitis, and arthritis.

“Further studies aiming to validate our findings using clinical data and clarify the underlying mechanisms behind the seasonal patterns of psoriasis are warranted.”

The Chinese and Australian study team included Dr Zhiwei Xu, a research fellow in the School of Public Health and Social Work at the Queensland University of Technology.