Exacerbation of psoriasis following vaccination with the Pfizer-BioNTech BTN162b2 mRNA COVID-19 vaccine during risankizumab treatment.

Dear Editor,

We report a 34‐year‐old Japanese man who had suffered from psoriasis vulgaris for 15 years. The Psoriasis Area and Severity Index (PASI) score before treatment was 19.2 (Figure 1a), but 4 weeks after commencing treatment with risankizmab, his rash had tended to improve (a decrease of the PASI score to 3.6) (Figure 1b). Eleven weeks after commencing the risankizumab treatment, the patient received his first Pfizer‐BioNTech BTN162b2 COVID‐19 mRNA vaccination, and the second vaccination 14 weeks later. From the day after the second vaccination, fatigue, fever, arthralgia, and pain at the injection site appeared. After 3 days, these symptoms improved, and then a rash appeared on the trunk and spread gradually to the extremities. He had visited our hospital during the 16‐week period of risankizumab administration, and erythematous scaly plaques had been found in a wide area covering the trunk and limbs; the PASI score at that time was 7.2 (Figure 1c). A skin biopsy showed regular psoriasiform hyperplasia, confluent parakeratosis, a diminished granular layer, and an increase of suprapapillary capillaries (Figure 1d). These features were consistent with psoriasis, which we considered to have worsened due to the COVID‐19 vaccine. The patient was given risankizumab as scheduled, and the rash improved (Figure 1e). There was no evident exacerbation of the eruption at the 28‐week consultation (Figure 1f).

FIGURE 1

(a) Before administration of risankizumab. Extensive erythema on the trunk. (b) Four weeks after the first dose of risankizumab. The rash has improved. (c) After the second dose of COVID vaccine. The rash has recurred and spread. (d) A skin biopsy shows regular psoriasiform hyperplasia, confluent parakeratosis, a diminished granular layer, and an increase of suprapapillary capillaries. (e) Twenty weeks (4 weeks after the third dose of risankizumab). The rash shows a tendency to diminish. (f) Twenty eight weeks (at the 4th dose of risankizumab). No exacerbation of the eruption is evident.

Sotoriou et al. and Megna et al. reported 14 and 11 cases of psoriasis exacerbation following COVID‐19 vaccination, respectively. Such exacerbation of psoriasis appears to be unrelated to the type of COVID‐19 vaccine used. Previous studies have demonstrated exacerbation of psoriasis following various types of vaccination (Bacille Calmette‐Guérin, tetanus‐diphtheria, and influenza vaccines). Following these vaccinations, significant increases in interleukin (IL)‐6 levels and, in turn, T helper 17 (Th17) cells have been noticed. Additionally, clinical trials have documented that the levels of IL‐2, IL‐12, tumor necrosis factor (TNF)‐α, and interferon (IFN)‐γ may increase following mRNA COVID‐19 vaccination. Therefore, it can be hypothesized that COVID‐19 mRNA vaccines induce an increment in cytokines, which can contribute to onset or flare of psoriasis in a subset of patients. In the present case, there was no exacerbation of the rash between the third and fourth doses of risankizumab. Also, at about the same time as the exacerbation of the eruption, there were adverse reactions due to the COVID‐19 vaccine. From these viewpoints, we considered that the rash exacerbation in our patient was not due to the diminished effect of risankizumab, and was an effect of the vaccine.

Previous literature suggests that COVID‐19 vaccines do not often induce psoriasis flare in patients undergoing treatment with biological agents. However, exacerbation during biologic treatment, such as that in the present case, has been reported. Although biologics may reduce the risk of flare, their use does not completely eliminate it. As COVID‐19 vaccination and booster vaccine shots continue to be administered worldwide, further studies should be carried out to clarify the mechanism of psoriasis exacerbation and to identify whether the frequency of exacerbation varies according to treatment context and patient background.

CONFLICT OF INTEREST

None declared.