by Colleen Reisz, MD January 3, 2023
Most Covid-related hair loss falls under the category of telogen effluvium. This type of hair loss is reversible and is characterized by an increase in shedding. Before the pandemic, telogen effluvium was most associated with the post-partum period. Pregnancy confers complex metabolic changes on the mother that alter fluid volume, insulin sensitivity, thyroid function and ectopic fat deposition. Shedding starts 3-4 months after delivery and corrects with time over 6 months to a year. Other recognized triggers for telogen effluvium include new medications, a prolonged medical illness, surgery and rapid weight loss associated with ketogenic diets, to name a few. Telogen causes the hair to shed from all over the scalp, distinguishing telogen from androgenetic alopecia, which targets the frontal scalp and crown. Telogen effluvium should be temporary, as the loss of the hair shaft initiates the renewal process. Hair grows approximately a centimeter a month, so the first signs of regrowth are often seen at the junction of the forehead and frontal hair line.
Telogen effluvium has recently been associated with COVID-19. Shedding from Covid starts earlier than telogen seen from other triggers. Initial case reports indicate shedding starts around day 45 and lasts just under 50 days. Over 60% of those experiencing COVID-related hair loss had moderate to severe disease. Patients who developed chronic inflammatory syndromes to Covid left the hospital on statins, antihypertensives, insulin-sensitizing drugs and anti-coagulants. Whether the hair loss was a direct result of the virus, the individual response to the virus, or the manner of treatment, remains to be studied. It may be that multiple factors combine to trigger the temporary loss of hair seen with Covid.
Covid-related hair loss, in most cases, will be a temporary disruption of growth/shed ratios that should normalize. The hair should regrow as the patient recovers. Individuals presenting months after Covid without improvement in hair shedding should undergo detailed pharmaceutical and nutraceutical histories related to their care. Vitamin D supplementation, a generic probiotic and topical minoxidil would be reasonable treatment strategies to stabilize hair growth while recovering from a systemic inflammatory disease such as that seen with Covid 19.
