A case of telogen effluvium followed by alopecia areata after SARS‐CoV‐2 infection

Dear Editor,

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection, which causes coronavirus disease 2019 (COVID‐19), is associated with various conditions, including autoimmune diseases, such as systemic lupus erythematosus, as it induces a cytokine storm. ¹ As key components of the immediate antiviral response, type I interferons (IFNs) are crucial for restricting viral replication and spread through autocrine and paracrine type I IFN receptor signaling. ²

We report herein a case of alopecia areata (AA) followed by telogen effluvium (TE) after SARS‐CoV‐2 infection. A 47‐year‐old woman experienced sore throat, headache, and fever of 38.5°C. A polymerase chain reaction test indicated that she was positive for SARS‐CoV‐2, and she was admitted to a designated medical institution for continuous high fever and severe pneumonia induced by COVID‐19. Three weeks after discharge, she experienced patchy hair loss on her head, and she was referred to our hospital 7 weeks after discharge (Figure 1a). Dermoscopic observation revealed black dots (blue arrow) and yellow dots (yellow arrow; Figure 1b). Flow cytometric analysis of peripheral blood mononuclear cells (PBMCs) showed a relatively high frequency of IFN‐γ‐producing T cells (10.2%) when compared to IL‐4‐producing T cells (0.64%) by the intracytoplasmic staining of the PBMCs (Figure 1c). The patient also experienced significant hair shedding (more than 200 hairs/day) from the whole scalp skin shortly after the AA improved (13 weeks after the COVID‐19 infection; Figure 1d). Dermoscopic observation revealed many vellus hairs on the scalp skin (Figure 1e). As a result of the hair plucking test, telogen hair accounted for about 40%. After 8 weeks, terminal hair regrowth was observed, and the excessive hair shedding had almost completely stopped.

FIGURE 1.

(a) Patchy hair loss on the scalp after COVID‐19 infection. (b) Dermoscopic observations revealing yellow dots (yellow arrow) and a black dot (blue arrow). (c) Flow cytometric analysis indicating a high frequency of IFN‐γ‐producing T cells when compared to IL‐4‐producing T cells by the intracytoplasmic staining of the PBMCs. (d) Diffuse hair loss followed by alopecia areata. (e) Dermoscopic observations reveal the regrowth of vellus hair on the scalp.

COVID‐19 is characterized by mild to severe respiratory illness due to overzealous cytokine production, the so‐called cytokine storm, especially IFNs from plasmacytoid dendritic cells. ³ This cytokine storm can lead to other disorders, including several autoimmune diseases. ¹ IFN‐α and IFN‐γ are also a crucial inducer of AA after viral infections. ² Indeed, there have been several case reports of the new onset of AA 1–2 months after the onset of COVID‐19. ⁴ Similarly, our case suffered from patchy hair loss on the scalp skin 5 weeks after the onset of COVID‐19. Of course, there is no direct way to prove that COVID‐19 is the cause of AA, but IFN‐γ dominant intracytoplasmic cytokine balance may indicate COVID‐19‐induced AA in our case.

Our patient also suffered from acute TE, which is characterized by significant hair shedding that lasts <6 months and results from an abrupt shift in the hair cycle from the anagen phase to the catagen phase and subsequent entry into the telogen phase. In our case, the COVID‐19‐induced cytokine storm may have caused not only high fever and severe pneumonia but also a sudden switch from the anagen to the catagen phase, followed by the telogen phase. ⁵ As the COVID‐19 pandemic continues, more patients may experience several types of hair loss. Careful observation of each hair loss symptom, and appropriate diagnosis and treatment selection are important.

CONFLICT OF INTEREST

None declared.