key: cord-0686639-gyi5q077 authors: Mintoff, D.; Pisani, D.; Livori, N.; Said‐Huntingford, I.; Baldacchino, G. title: SARS‐CoV‐2 mRNA booster vaccine‐associated lichenoid drug eruption date: 2022-04-25 journal: J Eur Acad Dermatol Venereol DOI: 10.1111/jdv.18149 sha: 2060af0d1a19a928c3c15926bb76c4677fb6d346 doc_id: 686639 cord_uid: gyi5q077 nan (SCAR) and erythema multiforme major were considered as the main differential diagnoses. The patient was prescribed prednisolone 0.5 mg/kg/day and lubricant ophthalmic drops (after review by an ophthalmologist). Serological testing, including a complete blood count with differential, biochemical profiling as well as Herpes Simplex PCR and Mycoplasma IgG and IgM were unremarkable. An incisional biopsy taken from the lesion on the shoulder revealed a perivascular and interstitial lymphohistiocytic inflammatory infiltrate in the upper dermis, which also featured occasional eosinophils (Fig. 2) . Endothelial swelling was appreciated however there was no convincing evidence of vasculitis. Lymphocytic infiltration of the basal layer of the epidermis with basal cell vascular damage was appreciated and pigment incontinence was focally identified. Civatte bodies were somewhat difficult to identify but, where present, were predominantly suprabasally located. Civatte body formation did not extend into the more superficial layers of the epidermis. The epidermis was variably acanthotic, focally spongiotic and parakeratinised in places. A Periodic acid-Schiff stain for fungal hyphae was negative. The overall findings were those of a lichenoid dermatitis. The paucity of the civatte bodies in this case argued against a diagnosis of erythema multiforme. On review 1 week after the initial consultation, the exanthem had significantly improved. The dose of oral steroids was tapered off by 5 mg every 3 days. The exanthem had completely resolved 2 weeks after oral corticosteroids were initiated. Vaccination-associated lichenoid drug eruption (LDE) is most widely associated with the Hepatitis B, influenza and herpes zoster vaccine with patients experiencing the adverse reaction being significantly older than patients with other reported ADRS (mean = 47 years). 1 LDE has been documented in the context of Oxford-AstraZeneca, 2 Moderna 3 and also Pfizer-BioNTech 4 COVID-19 vaccine. This report however is the first to document LDE to a "booster" dose of the COVID-19 vaccination schedule. The effectiveness of the booster (third) dose of Pfizer-BioNTech-CoV-2 mRNA vaccine is established. 5 A recent review of booster COVID-19 mRNA vaccine adverse event reporting system (VAERS) looking at 39286 reports processed between September 22, 2021 and February 6, 2022 (in patients older than 18 years) found that 92.4% of VAERS were non serious (most commonly headache, fever and pain). 6 64.3% of 332 588 patients who received the Pfizer-BioNTech booster vaccine reported an injection site reaction. No specific cutaneous ADR was reported. 6 The patient in this case sustained a cutaneous ADR to the booster dose of the COVID-19 mRNA vaccine. The case highlights the importance of thorough drug history taking in patients presenting with cutaneous eruptions, histopathological correlation as well as for the need of appropriate documentation and adverse drug event reporting. In the setting of the COVID-19 pandemic, dermatologists may play a vital role in establishing reactions to COVID-19 booster vaccination (which may require the need for diagnostic "challenging") especially when considering the restricted freedom of movement of individuals who are not fully vaccinated. Lichen planus and lichenoid drug eruption after vaccination Exuberant lichenoid eruption after Oxford-AstraZeneca COVID-19 vaccine: a singular case Cutaneous reactions after SARS-CoV-2 vaccination: a cross-sectional Spanish nationwide study of 405 cases New-onset cutaneous lichen planus triggered by COVID-19 vaccination Effectiveness of a third dose of the BNT162b2 mRNA COVID-19 vaccine for preventing severe outcomes in Israel: an observational study Safety monitoring of COVID-19 vaccine booster doses among adults -United States The patient gave written informed consent for the publication of his case details as well as clinical photography.