Psoriasis Linked With Risk for Severe and Rare Infections

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The risk for severe and rare infections in patients with psoriasis—mild or severe—is assessed.

Patients with psoriasis have an increased risk for severe and rare infections, according to findings from a study published in the British Journal of Dermatology.

The population-based cohort study used data from Danish administrative registries to assess the incidence and risk for severe and rare infections in Danish patients with psoriasis and the matched general population.

Eligible participants aged 18 years or older from January 1, 1997, to December 31, 2018, were enrolled. Each patient with psoriasis was matched according to sex and exact date of birth with 6 individuals from the general population in Denmark.

The study outcome was the occurrence of severe infections, defined as those that required evaluation at a hospital, and/or rare infections, including HIV, tuberculosis (TB), hepatitis B virus, and hepatitis C virus.

A total of 94,450 patients with psoriasis and 566,700 general population reference individuals were matched for age and sex. The median (interquartile range) age was 52.3 years (38.3-64.1), and 50.2% were women.

In patients with psoriasis, the incidence rate (IR) of any infection (severe and rare) per 100,000 person-years was 3104.9 (95% CI, 3066.6-3143.7), compared with 2381.1 (95% CI, 2,367.6-2,394.6) for the control group. The IR of any severe infections for patients with psoriasis was 3080.6 (95% CI, 3042.5-3119.3), compared with 2364.4 (95% CI, 2350.9-2377.9) for the control group.

For patients with psoriasis, the IR of any rare infections was 42.91 (95% CI, 38.89- 47.35), compared with 31.79 (95% CI, 30.34-33.31) for control individuals. The IR for HIV was 5.95 (95% CI, 4.57-7.74), 7.46 (95% CI, 5.89-9.44) for TB, and 29.89 (95% CI, 26.56-33.63) for hepatitis. Psoriasis was associated with an increased risk for any rare infection (adjusted hazard ratio [aHR] 1.34 [95% CI, 1.20-1.50]), which was attributed to an increased incidence of HIV and hepatitis but not TB.

The IR for patients with severe psoriasis (3847.7 [95% CI, 3754.3-3943.4]) was higher vs that of the control group. The aHR between patients with severe psoriasis and the matched general population was 1.58 (1.54-1.62).

For patients with mild psoriasis, the IR (3003.5 [95% CI, 2964.1-3043.4]) was higher vs the IR for the control group. The aHR between patients with mild psoriasis and the matched general population was 1.26 (95% CI, 1.25-1.28).

Study limitations include the absence of data for confounding factors, such as weight, body mass index, and smoking status, as well as the potential of surveillance bias. In addition, psoriasis severity indexes such as the Psoriasis Area Severity Index were not used.

“Clinicians should be aware of the increased risk of severe and rare infections in patients with severe psoriasis so investigation and treatment can be initiated early,” the researchers stated.

Disclosure: This research was supported by Novartis. Several of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.


Loft N, Skov L, Richardson C, Trivedi V, Alarcon I, Egeberg A. A nationwide population-based cohort study of the incidence of severe and rare infections among adults with psoriasis in Denmark.Br J Dermatol. Published online April 5, 2022. doi:10.1111/bjd.21595

This article originally appeared on Dermatology Advisor