COVID Induced Telogen Effluvium (CITE): An Insight
Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) has emerged as a serious global pandemic, since late of 2019. COVID‑19 has been associated with varied skin manifestations like vesicular, maculopapular, urticarial, acro‑ischemic lesions, and others. Hair loss is one of the persistent symptoms in most of the COVID‑19 survivors. Recently an article giving an insight into COVID induced telogen effluvium was published in the Indian Dermatology Online Journal.

TE is one of the most common forms of non-scarring hair loss that is characterized by a diffuse hair loss within months of a significant systemic stress because of premature follicular transition from the anagen (active growth phase) to the telogen (resting phase). The telogen phase lasts approximately 3 months, after which excessive hair loss ensues. Acute TE (ATE) usually occurs 3 months after the stressful event and is self-limited lasting up to 6 months. Chronic TE occurs after 6 months. It has many known triggers like stressful events, drugs, endocrine disease, major surgery, febrile illnesses, and nutritional deficiencies.
Hair loss due to COVID-19 can be attributed to telogen effluvium (TE) resulting from infection or a resultant stress response. Up to 80% of patients have symptoms lasting for 4–12 weeks or longer post COVID‑19. According to a study on 87 Japanese patients hair loss was seen in 18.4% of patients.[6]
Usually females present with TE to dermatologists because-
They are more susceptible for stress due to delivery, abortion, and others
Females are more disturbed by hair shedding than males therefore more likely to seek medical attention
Long hair is more easily noticed by the females during hair shedding
The authors encountered a good number of post-covid TE in the early post‑covid period (1–3 months) with classic TE like presentation in their tertiary hospital. The most common trichoscopic findings were decreased hair density, the presence of empty follicles, or short regrowing hair. FotoFinder trichogram showed telogen hair root and shafts with lesser pigmentation and thickened root without angulations. It was club shaped, resembling an ear bud. Recently, the percentage of ATE has increased in comparison with the previous years; this could be attributed to the pandemic of COVID‑19 during this period. The possible mechanisms of COVID-19 induced hair loss could be:
Pro‑inflammatory cytokines: SARS-CoV‑2 elicits strong antiviral responses, especially via interferon, which is a well‑known TE‑inducer molecule. Interleukin (IL)‑6 levels are increased in severe COVID‑19 which acts on the hair follicle (HF), causing collapse of immune privilege and induction of catagen phase as well as causes local inflammation. High levels of IL‑4 especially in the elderly, also regulate keratinocyte apoptosis in HF. Additional molecules showing high levels in COVID‑19 are metalloproteinase 1 and 3 and IL‑1β, which may inhibit the HF growth. Cytokine storm can initiate the development of TE by damaging the matrix cells. Monocytes and macrophages infected by SARS‑CoV‑2 can produce pro‑inflammatory cytokines that play a crucial role in the development of COVID‑19‑related complications.
Direct viral damage to hair follicles (ADE phenomenon): Initially it is due to the superficial spike glycoproteins characteristic of SARS-CoV‑2, which binds to angiotensin I‑converting enzyme‑2 on host cells, allowing pathogen entry. Non‑neutralizing virus‑specific antibodies (NAbs) are present in patients with SARS-CoV‑2 infection and are able to promote virus entry into host cells through interaction with Fcγ and/or complement receptors.
Coagulation cascade with microthrombi formation. In severe COVID‑19 infections with coagulation cascade activation, decreased concentration of anticoagulant proteins occur due to decreased production and increased consumption. These factors can lead to microthrombi formation, which may occlude hair follicle blood supply.
Other possible causes of hairloss: role of androgens and their receptor on hair follicle, therapies administered for COVID‑19 and psychological distress
Even if a patient has never developed a fever or COVID‑19, he/she may still see hair shedding.
Management
Most people see their hair regain its normal fullness within 6–9 months.
Topical minoxidil is prescribed in many reported patients, there is no strong evidence to suggest that it is efficacious for TE.
Educating the patient on the self‑limiting natural course of the condition is a crucial component of management.
The hair will eventually stop shedding and begin to grow back, but it may take up to 18 months for hair thickness to return to baseline.
Conclusion
To conclude in the current era of pandemic, SARS‑CoV‑2 infection should be suspected and investigated in a patient who presents with acute TE. It is a self limited disease and counselling of patients is the focus of management.
Source- Inamadar AC. Covid induced telogen effluvium (CITE): An insight. Indian Dermatol Online J 2022;13:445-8.