In this study, the incidence of relapse in individuals affected by AA after COVID-19 infection in the period from March to October 2020 was examined through a questionnaire and compared with non-infected subjects. As soon as the COVID-19 pandemic started, scientists began to notice and investigate dermatological manifestations related to COVID-19 infection.
With COVID-19 spreading all around the world from March 2020, evidence both from physicians and patients started to suggest an increase of hair loss after COVID-19 recover. It could be hypothesized that physical and emotional stress experienced during COVID-19 infection could lead to telogen effluvium-like conditions which usually are reported to occur a few months after a stressful event (e.g., emotional stress, surgery, high fever, etc.). Limited published data are available on this topic , but much evidence is currently available from public data or reported from clinical experience. However, we could not find any study on AA relapse in subjects affected by this condition during the COVID-19 pandemic in Italy.
Relapse in subjects with AA from an Italian cohort of subjects affected both by AA and COVID-19 was found to statistically increase during the pandemic (42.5% vs 12.5%). These data are in line with a previous Turkish study from Kutlu et al.  in the period from May 2019 to May 2020.
AA is a well-studied autoimmune and chronic inflammatory disease [4, 5] in which psycho-emotional stress may also be involved .
Stress derived from quarantine conditions such as that deriving from health and economical insecurity could be proposed as a triggering factor of AA relapse and persistence reported in this study. Indeed, stress is reported to have an impact on other skin conditions in which stress is reported to exert a role [12, 13].
Most interesting, the generalized inflammation deriving from COVID-19 infection also has to be taken into account, considering the role of inflammation in AA.
Recently, Bulat and collaborators  reported an overactivation of T cells in patients with COVID-19, which reflects an increase in the Th17 subset of CD4+ T cells. This leads to increased production of both interleukin-17 (IL-17) and IL-22 cytokines, the main triggers of cytokine release storm (CRS) leading to the rapid and severe deterioration of the condition of patients with COVID-19 . AA is itself associated with the dysregulation in systemic type 17 and type 2 cytokines, and IL-17 has been proposed as a target for AA treatment . Indeed, IL-17 represents a systemic inflammatory signature of AA and, most interesting, is also reported to contribute to disease-associated psychological morbidity . Increased plasma levels of the type 2 cytokines (IL-33, IL-31, and IL-15) were reported in subjects with AA, in addition to type 17 cytokines (IL-17A, IL-21, IL-23, and IL-17F) and the levels of these cytokines positively predict depression score .
Taken together, this evidence is coherent with the so-called brain–skin axis  which clearly explains the strict relationship between psychological triggers and changes in the hair growth cycle.
A limitation of this study is that no clinical investigations were conducted apart from photographic evaluations to assess AA relapse. Additional clinical investigations are currently underway.