The association of hair loss and coronavirus infection COVID-19 – facts and hypotheses

Abstract

The main manifestations of COVID-19 are primarily interstitial pneumonia and respiratory failure. No less than 20% of patients have variable skin rashes, which try to be interpreted as markers and predictors of the peculiarities of the course of coronavirus infection. In addition, hair loss is a characteristic manifestation of COVID-19, and the salivary follicles are regarded as a target for SARS-CoV-2. The most common variants of alopecia in patients with a new coronavirus infection or vaccine-induced alopecia are acute telogenic, nondescript, and androgenetic alopecia. This review provides information on the most common variants of hair loss in patients with SARS-CoV-2 infection, the features of their manifestations, and possible mechanisms of development. Acute telogenic hair loss is the most common variant of SARS-CoV-2-induced alopecia, is characteristic of patients with subacute course of COVID-19 and can be combined with trichodynia, anosmia and aguvia, which are markers of nervous syste damage. Given the variability in the time of onset after infection, a heterogeneous pathogenesis of alopecia can be assumed. Nested alopecia after COVID-19 is often a relapse of the disease, its severity and frequency do not correlate with the severity of the infectious disease, and its prevalence in women indicates the importance of hormonal factors in its development. Androgenetic alopecia may be a predictor of high risk of infection, severe course, and recurrence of COVID-19. The first two variants of alopecia may be associated with COVID-19 vaccination, and the latter is a predictor of inadequate immune response to vaccine administration. The mechanisms of the damaging effects of SARS-CoV-2 on hair follicles have not been fully deciphered and are most likely complex, with different leading links in different types of hair loss. Deciphering these mechanisms may provide prerequisites for understanding the mechanisms of COVID-19 damage to other tissues and organs.