Psoriasis is a skin condition caused by an increased production of skin cells, and is thought to result from abnormalities in the immune system. It is characterised by systemic inflammation, which also affects other systems of the body, including the eyes and cardiovascular system.

There is some evidence to suggest that patients with psoriasis are more likely to experience fatigue, and a recently published study from a group in Taiwan has been looking at whether psoriasis is associated with an increased risk of developing CFS.

The investigators identified – from the Taiwanese National Health Insurance database – 2,616 patients diagnosed with psoriasis between 2004 and 2008, as well as 10,464 individuals without the condition. They then looked at how many people in each group were subsequently diagnosed with chronic fatigue syndrome (as defined using 1994 CDC/Fukuda criteria) up until the end of 2011.

The research found that a higher proportion of patients with psoriasis received a diagnosis of CFS during the follow-up period (1.91%) compared with individuals without psoriasis (1.20%), and a statistical test showed that the difference between the groups was greater than one would expect just by chance.

Another test – which adjusted the results to take account of differences in sex, age, and other conditions – showed that the risk of developing CFS was nearly one-and-a-half times greater in patients with psoriasis than in individuals without. This association was more marked in men and in older individuals, and was reduced after treatment with phototherapy or immune medications.

A diagnosis of CFS is likely to encompass a range of diverse illnesses, including but not limited to what we would define as ME. Nevertheless, this study does provide more evidence that an altered immune system is involved in the pathology of ME.

Immune abnormalities in ME/CFS are also currently being investigated in ME Research UK-funded studies in Vermont, Alabama, Germany, and the UK.