Dermatologica Sinica

: 2022  |  Volume : 40  |  Issue : 1  |  Page : 52--53

AZ arm: Delayed cutaneous reaction to ChAdOx1 nCoV-19 (AZD1222) vaccine

Wei-Kai Hung1, Ching-Chi Chi2, Shu-Hui Wang3,  
1 Department of Dermatology, Chang Gung Memorial Hospital, Taoyuan City, Taiwan
2 Department of Dermatology, Chang Gung Memorial Hospital; College of Medicine, Chang Gung University, Taoyuan City, Taiwan
3 Department of Dermatology, Far Eastern Memorial Hospital, New Taipei City, Taiwan

Correspondence Address:
Dr. Shu-Hui Wang
Department of Dermatology, Far Eastern Memorial Hospital, No. 21, Sec 2, Nanya S. Road, Banciao, New Taipei City 22060

How to cite this article:
Hung WK, Chi CC, Wang SH. AZ arm: Delayed cutaneous reaction to ChAdOx1 nCoV-19 (AZD1222) vaccine.Dermatol Sin 2022;40:52-53

How to cite this URL:
Hung WK, Chi CC, Wang SH. AZ arm: Delayed cutaneous reaction to ChAdOx1 nCoV-19 (AZD1222) vaccine. Dermatol Sin [serial online] 2022 [cited 2022 Jul 7 ];40:52-53
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Full Text

Dear Editor,

In the global COVID-19 pandemic, different types of vaccines against SARS-CoV-2 have been developed at an unprecedented speed. The Taiwanese government has granted emergency use authorization for SARS-CoV-2 vaccines, including the ChAdOx1 nCoV-19 (AZD1222, frequently termed as AZ), mRNA-1273 (Moderna), BNT162b2 mRNA, and MVC-COV1901 vaccines. However, various cutaneous adverse reactions have been reported.[1] Herein, we reported a case of delayed cutaneous reaction after the first dose of the AZ vaccine.

A 59-year-old woman with a history of psoriasis presented with a large erythematous, edematous plaque on her left arm surrounding the injection site 3 days after receiving the first dose of the AZ vaccine [Figure 1]. In addition to the localized erythema, multiple erythematous papules coalescing into plaques also appeared on her right upper back [Figure 2]. There were no concurrent constitutional symptoms, and the patient denied previous allergies to regular vaccinations. Oral antihistamines and methylprednisolone were given and the skin lesions almost cleared 1 week later. The lymphocyte activation test (LAT), measuring the production of granulysin and granzyme B, was performed to determine lymphocyte sensitization by the causative medicine. The cutoff value was calculated by using the values of mean and twofold standard deviation from the tolerant controls. LAT showed a positive reaction to polysorbate 80 (3.06 fold increase of granulysin compared to the solvent control [cutoff value: 2.43 fold]; 3.66 fold increase of granzyme B compared to the solvent control [cutoff value: 2.60 fold]).[2]{Figure 1}{Figure 2}

Vaccination is an evidence-based measure to combat the COVID-19 pandemic. However, the emergence of adverse events reported by social media and academic articles may cause fear and anxiety in the public, leading to vaccination hesitancy.[3] In Western countries, the delayed large local cutaneous reaction or “COVID arm” was frequently reported after receiving the mRNA-based vaccines, especially the Moderna vaccine.[1] In a registry-based study, 414 cases that developed cutaneous reactions to Moderna or BNT162b2 vaccines were reported.[1] The delayed large local cutaneous reaction is the most common skin reaction after the administration of the Moderna vaccine (66% at first dose and 30% at second dose) and is less often after the BNT162b2 vaccine administration (15% at first dose and 18% at second dose). Unlike these mRNA-based vaccines, the AZ vaccine is a replication-deficient chimpanzee adenovirus-vectored vaccine expressing the SARS-CoV-2 spike protein. The delayed large local cutaneous reaction following AZ vaccine administration was relatively unrecognized and unreported. Four cases in a series and one case report were found to date.[4],[5] In all five previously reported cases, the local reactions were confined to the AZ vaccine injection site. However, cutaneous reactions beyond the injection site developed in our case. This delayed-type skin reaction has not been considered as a contraindication to subsequent vaccination and the symptoms resolved accordingly after proper management with a favorable clinical prognosis in all reported cases.[6]

The exact pathomechanism of the delayed large local cutaneous reaction is still unclear. Skin biopsy specimens obtained from the previous cases with the delayed cutaneous reaction after Moderna and AZ vaccines showed superficial perivascular and perifollicular lymphocytic infiltration with rare eosinophils, which supported the suspicion of T-cell-mediated (or delayed-type) hypersensitivity reaction.[4],[7] In allergic reactions to vaccines, these phenomena are not commonly attributed to the active ingredient but the inactive excipient.[3],[8] The polyethylene glycol and polysorbate 80 have been suggested as possible etiologies in the mRNA-based vaccines and AZ vaccine, respectively.[3],[8] However, no confirmation tests were performed in the previously reported cases. In our case, although the lack of histopathologic information, LAT with polysorbate 80 was performed with a positive reaction. To the best of our knowledge, this may be the first description of a patient presented with delayed large local cutaneous reaction to the AZ vaccine with confirmed polysorbate 80 allergy in Taiwan.

In summary, we presented a case of delayed large local cutaneous reaction following AZ vaccination with confirmed hypersensitivity reaction to polysorbate 80. As dermatologists in this COVID-19 pandemic requiring widespread vaccination, recognizing the morphology and characteristics of cutaneous reaction after vaccination is crucial to developing the subsequent management strategies. Reporting of this case may serve as a reminder for our daily practice to prevent unnecessary tests or overtreatment in reactions with benign courses.


The authors would like to thank Prof. Wen-Hung Chung, Dr. Chun-Bing Chen, and the Drug Hypersensitivity Clinical and Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan, for the technical help and consultation.

Ethical approval

This study was approved by the institutional review board of the Chang Gung Medical Foundation (IRB No. 202200144B0 on Febuary 8th, 2022) and the patient consent form has been obtained.

Financial support and sponsorship


Conflicts of interest

Prof. Ching-Chi Chi, an editorial board member of Dermatologica Sinica, had no role in the peer review process or decision to publish this article. The other authors declared no conflicts of interest in writing this paper.


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