Comment on 'Morphoea following COVID-19 vaccination'.

Dear Editor,

Several strategies have been adopted in the fight against the COVID‐19 pandemic. , We read with great interest the recently published paper in Clinical and Experimental Dermatology by Oh et al., reporting the case of a 47‐year‐old woman who developed superficial morphoea 3 weeks after the second dose of the Pfizer‐BioNTech vaccination. The authors also suggested three pathogenetic mechanisms that could explain the correlation between vaccination and morphoea development, but they did not explain which of these they thought would be the most likely.

Subsequently, Sookaromdee and Wiwanitkit responded to Oh et al., posing some interesting thoughts that we would like to explore further. We agree with Sookaromdee and Wiwanitkit that the reported case has many limitations, including a lack of medical data such as comorbidities or current therapies of the patient that could relate to the vaccination and the development of morphoea; the missing details may or may not correlate the two events. We also consider that the period between vaccination and morphoea development is too long to confirm the relationship. Moreover, we disagree with the authors that there is a need to routinely evaluate vaccination history in patients with recent‐onset morphoea, as there is a lack of strong evidence. Even though morphoea following COVID‐19 vaccination has been reported in the literature, , the cases described to date verge more toward generalized morphoea, confirming our hypothesis of a coincidence.

In our department, we have seen many reactions following COVID‐19 vaccination. In addition to the well‐established reactions such as local injection site reactions, morbilliform eruptions and pityriasis rosea‐like reactions, we have also encountered other conditions such as shingles, alopecia areata, and worsening of chronic inflammatory diseases such as psoriasis, atopic dermatitis and hidradenitis suppurativa. , These types of reactions have been widely described in the literature and allow us to relate the onset of the manifestations to the COVID‐19 vaccination. Furthermore, cutaneous reactions related to COVID‐19 vaccination have also been reported following the booster dose. , ,

To date, there are still too few reports about the occurrence of post‐vaccination morphoea. We believe that further studies or case reports are needed to better explain the pathogenetic mechanism and understanding this possible correlation. Vaccination against COVID‐19 should not be discouraged on the basis of a small number of adverse cutaneous reactions.