"Knowledge about SARS-CoV-2 vaccine safety and benefits is evolving to support decision-making about use of these vaccines. Although benefits of these vaccines greatly overweight risks associated with acquisition of infection, the benefit-risk balance should be communicated to patients."
A Case Report and Narrative Review
Hair loss is a common presentation in primary care. Among various causes of hair loss, alopecia areata (AA) represents 18.2% of the causes  and has a lifetime risk of approximately 2% [2,3]. AA is a patchy nonscarring alopecia with underlying autoimmunity against hair follicles with resultant dystrophy of the hair follicle at the anagen phase of growth [3,4]. Severe forms of AA include alopecia totalis (all scalp hair) and universalis (entire body). Despite multiple underlying pathophysiological mechanisms, there are two well-established primary explanations. The immune dysregulation with loss of immune privilege of hair follicles and genetic predisposition [3,5]. Other factors include infections, drugs, and vaccines with consequent immune dysregulation and development of AA.
Wise, Kiminyo, and Salive's 1997 study was among the earliest reports of hair loss after routine immunizations in their case series . It is suggested that vaccines via antigen presentation, cytokine production, epitope spreading, polyclonal activation of B cells, and other mechanisms of anti-infectious immune response and autoreactivity potentially trigger autoimmunity . Regarding severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines, there is a theoretical risk of inducing autoimmunity and a number of reports of different autoimmune sequela ; however, most frequently used messenger ribonucleic acid (mRNA) vaccines have excluded patients with a history of autoimmune conditions from their clinical trials. The US Food and Drug Administration has raised the concern of possible precipitation of rheumatoid arthritis after SARS-CoV-2 vaccination . Pfizer vaccine developers have included a list of rare complications, including myocarditis and skin reactions, in the information leaflet, but AA was not listed.
In addition to the morbidity burden of AA, it is distressing to affected patients and is associated with major psychosocial sequelae and reduced quality of life . This report presents a patient with alopecia universalis recurrence precipitated by the SARS-CoV-2 vaccine.
Knowledge about SARS-CoV-2 vaccine safety and benefits is evolving to support decision-making about use of these vaccines. Although benefits of these vaccines greatly overweight risks associated with acquisition of infection, the benefit-risk balance should be communicated to patients. There is currently a lack of clear-cut recommendations about screening for autoimmunity in patients receiving SARS-CoV-2 vaccines and autoimmunity in this context is multifactorial with multiple modifiers. Due to the growing reports of autoimmunity flares including AA, healthcare providers should remember to enquire about personal and/or family history of autoimmunity. This would allow for proper patient-centered counselling and enable patients to take informed health decisions in their best interest.
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