A systematic review of acute telogen effluvium, a harrowing post-COVID-19 manifestation

Abstract

This systematic review focuses on the clinical features, physical examination findings, outcomes, and underlying pathology of acute telogen effluvium (TE), a type of diffuse hair loss, occurring in COVID-19 recovered patients. MEDLINE/PubMed and Embase databases were queried till October 2021 to identify studies reporting acute TE occurring after COVID-19 recovery. Data were obtained from 19 studies which included 465 patients who were diagnosed with acute TE. The median age of these patients was 44 years and 67.5% were females. The most common trichoscopic findings were decreased hair density, the presence of empty follicles, or short re-growing hair. The mean duration from COVID-19 symptom onset to the appearance of acute TE was 74 days, which is earlier than classic acute TE. Most patients recovered from hair loss, while a few patients had persistent hair fall. Our results highlight the need to consider the possibility of post-COVID-19 acute TE in patients presenting with hair fall, with a history of COVID-19 infection, in the context of COVID-19 pandemic. Despite being a self-limiting condition, hair loss post-COVID-19 is a stressful manifestation. Identifying COVID-19 infection as a potential cause of acute TE will help the clinicians counsel the patients, relieving them from undue stress.
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Full text

Received: 14 November 2021
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Accepted: 19 December 2021
DOI: 10.1002/jmv.27534
REVIEW
A systematic review of acute telogen effluvium, a harrowing
post‐COVID‐19 manifestation
Nabeel Hussain
1
|Preeti Agarwala
2
|Kinza Iqbal
3
|
Hanaa Mohamed Sheikh Omar
4
|Gurusha Jangid
5
|Vraj Patel
6
|
Sawai Singh Rathore
5
|Chandani Kumari
7
|Felipe Velasquez‐Botero
8,9
|
Guadalupe Abigail Benítez López
9
|Yogesh Vishwakarma
7
|Airin Parvin Nipu
10
|
Noman Khurshid Ahmed
3
1
Saba University School of Medicine,
The Bottom, The Netherlands
2
Rajshahi Medical College and Hospital,
Rajshahi, Bangladesh
3
Department of Internal Medicine, Dow
Medical College, Dow University of Health
Sciences, Karachi, Pakistan
4
Zamzam University of Science & Technology,
Mogadishu, Somalia
5
Dr. Sampurnanand Medical College, Jodhpur,
Rajasthan, India
6
Smt NHL Municipal Medical College,
Ahmedabad, Gujarat, India
7
American University of Barbados, Wildey,
St. Michael, Barbados
8
Universidad CES, Medellin, Colombia
9
Larkin Community Hospital, Miami,
Florida, USA
10
University of Arkansas at Pine Bluff, Pine
Bluff, Arkansas, USA
Correspondence
Sawai Singh Rathore, Dr Sampurnanand
Medical College, Jodhpur, Rajasthan 342003,
India.
Email: sawais.rathore77@gmail.com
Abstract
This systematic review focuses on the clinical features, physical examination findings,
outcomes, and underlying pathology of acute telogen effluvium (TE), a type of diffuse hair
loss, occurring in coronavirus disease 2019 (COVID‐19) recovered patients. MEDLINE/
PubMed and Embase databases were queried till October 2021 to identify studies re-
porting acute TE occurring after COVID‐19 recovery. Data were obtained from 19 stu-
dies, which included 465 patients who were diagnosed with acute TE. The median age of
these patients was 44 years and 67.5% were females. The most common trichoscopic
findings were decreased hair density, the presence of empty follicles, or short regrowing
hair. The mean duration from COVID‐19 symptom onset to the appearance of acute TE
was 74 days, which is earlier than classic acute TE. Most patients recovered from hair loss,
while a few patients had persistent hair fall. Our results highlight the need to consider the
possibility of post‐COVID‐19 acuteTE in patients presenting with hair fall, with a history
of COVID‐19 infection, in the context of COVID‐19 pandemic. Despite being a self‐
limiting condition, hair loss post‐COVID‐19 is a stressful manifestation. Identifying
COVID‐19 infection as a potential cause of acute TE will help the clinicians counsel the
patients, relieving them from undue stress.
KEYWORDS
hair loss, post‐COVID‐19, TE, telogen effluvium, trichoscopy
1|INTRODUCTION
At the end of the year 2019, a new infectious pathogen severe
acute respiratory syndrome (SARS‐CoV‐2) associated with an
unexplained cause of pneumonia arose in China, which was later
coined as coronavirus disease 2019 (COVID‐19).
1
The clinical
manifestation of COVID‐19 is quite diversified, ranging from mild
symptoms to life‐threatening respiratory failure, septic shock,
and eventually multiorgan failure.
2,3
The most frequently
encountered clinical manifestations of COVID‐19 infection in-
clude fever, dry cough, fatigue, sore throat, dyspnea, headache,
vomiting, diarrhea, anosmia, and ageusia.
4–6
The dermatological manifestations of COVID‐19, which were
initially considered to be of little significance, have proven to be
varied and sophisticated. According to published literature, the
incidence of dermatological lesions in COVID‐19 ranges from
0.6% to 20.4%.
7
Hair loss after recovery from COVID‐19 is be-
coming a prominent dermal manifestation, with acute telogen
J Med Virol. 2021;1–11. wileyonlinelibrary.com/journal/jmv © 2021 Wiley Periodicals LLC
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1

effluvium (TE) being a common occurrence. TE is defined as dif-
fuse hair loss that occurs 2–3 months after a stressful
event like febrile states, drugs, and postpartum period. The pre-
cipitating event induces hair loss by prematurely terminating the
anagen phase and conversion to the catagen and telogen pha-
ses.
8,9
The body responds to infection with COVID‐19 by es-
tablishing a proinflammatory state that causes tissue damage and
associated sequelae. proinflammatory cytokines are produced
and the process of anticoagulation is disrupted, which might
cause TE in hair follicles through a systemic inflammatory
response.
8
This systematic review aims to compile and illustrate the clinical
characteristics, physical examination findings, outcomes, and possible
pathology behind acute TE occurring in COVID‐19 recovered
patients.
2|METHODS
This systematic review was performed and reported according to the
Preferred Reporting Items for Systematic Reviews and Meta‐analyses
(PRISMA) guidelines.
10
2.1 |Search strategy
A literature search was carried out using MEDLINE/PubMed and Embase
databases for studies published from December, 2019 till 5th of October,
2021. The search terms used included “Coronavirus,”“Covid‐19,”“SARS‐
CoV‐2,”“Telogen effluvium,”“TE,”“Hair loss,”“Hair fall,”“Scalp,”and “late
manifestation.”Studies were included from all over the world without any
language restriction. Titles and abstracts of the articles retrieved from the
literature search were screened by twoauthors(P.A.andC.K.).These
authors ascertained the relevance of the studies based on predetermined
eligibility criteria. Additional relevant studies were identified by manually
inspecting the reference lists of the included studies. PRISMA flow dia-
gram is illustrated in Figure 1.
2.2 |Eligibility criteria
Only those articles that met our predefined eligibility criteria were
included in the analysis. Inclusion criteria consisted of (1) adult par-
ticipants ≥18 years of age, (2) observational studies, case reports, and
case series, and (3) studies reporting patients recovered from
laboratory‐confirmed SARS‐CoV‐2 infection presenting with hair loss
FIGURE 1 PRISMA flow diagram: representation of systematic literature search and study selection process. PRISMA, Reporting Items for
Systematic Reviews and Meta‐analyses. Source: Moher et al.
11
2
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HUSSAIN ET AL.

weeks to months after infection. Review articles, posters, and du-
plicate publications were excluded.
2.3 |Quality assessment
The risk of bias assessment and quality appraisal of observational
studies was done with the help of the Newcastle‐Ottawa Scale.
12
Two investigators (Y. V. and V. P.) independently employed the
Newcastle‐Ottawa Scale for evaluating the quality of each included
study. Quality appraisal for included case reports and case series was
done using a tool established by Murad et al.
13
With the aid of this
tool, three authors (K. I., N. K. A., and G. J.) analyzed all articles on
four domains, including election, ascertainment, causality, and re-
porting. Studies were graded as good, fair, or poor quality.
2.4 |Data extraction
For each study, the following details were obtained: author, country
of origin, study design, sample size, mean age, previous history of hair
loss, physical exam findings, duration after recovery from COVID‐19,
duration from COVID‐19 symptoms to the onset of acute TE, treat-
ment of COVID‐19, treatment of acute TE, and outcomes of acuteTE.
3|RESULTS
Of the 1810 articles obtained from the initial database search, 1034
articles remained after the removal of duplicate articles. After
screening these articles for eligibility, 946 articles were removed as
they focused on dermatologic manifestations of COVID‐19 other
than TE. Subsequently, 88 full‐text articles pertaining to the objective
of the manuscript were reviewed. A total of 19 articles met our priori
inclusion criteria and were included in this systematic review
(Figure 1).
A total of 632 patients with a history of COVID‐19 infection were
included from 19 studies.
8,9,14–30
Out of these 632 patients, 465 patients
reported hair loss after recovery from COVID‐19 and were subsequently
diagnosed with acute TE. The median age of these patients was 44 years
(which ranged from 34 to 64 years), with 67.5% of them being female.
Most of the included studies were from the United States (four studies),
followed by Italy (three studies), Spain (two studies), and one study each
from France, China, Thailand, Pakistan, Colombia, Turkey, and Portugal.
The data of two studies (97 patients) were from multinational registries
(Table 1).
3.1 |Clinical characteristics of patients during
COVID‐19 infection
AtthetimeofCOVID‐19 infection, the most prevalent symptoms in
these patients were fever (59%), cough (23.6%), dyspnea (16.5%),
anosmia (15%), ageusia (13.5%), and fatigue (12%). Other COVID‐19
symptoms included diarrhea (6.4%), myalgia (5.5%), headache (4.26%),
chest pain (2.84%), and coryza (1.2%). The most prevalent comorbidities
in these patients were hypertension (27%), diabetes mellitus (17%), and
dyslipidemia (6%). Other less frequently documented comorbidities in-
cluded asthma (2.7%), anxiety disorder (0.75%), and major depressive
disorder (0.38%). During the phase of COVID‐19 infection, about 39% of
patients had a history of hospitalization with an average hospital length of
stay of 12 days. Medications used for the management of COVID‐19
varied and the most frequently used medications were paracetamol, an-
tibiotics, anticoagulant, steroids, tocilizumab, and hydroxychloroquine.
Clinical features at the time of COVID‐19 infection are summed up in
Table 2.
3.1.1 |Clinical features of TE in COVID‐19
recovered patients
COVID‐19 recovered patients presented with hair loss, which was
later diagnosed as acute TE on an average of 67 days after recovery
from infection, with 34 days being the earliest. Similarly, the mean
duration from COVID‐19 symptom onset to the appearance of acute
TE was 74 days. Table 3illustrates the clinical findings of acute TE
observed in COVID‐19 recovered patients.
3.2 |Physical examination findings
Physical examination of the scalp depicted a positive telogen hair pull
test in about 79% of patients. Telogen hair pull test is based on the
concept of “gentle”hair pulling to induce telogen hair shedding. It aids
in determining the extent and location of hair loss. Trichoscopic find-
ings most commonly included decreased hair density with the pre-
sence of empty follicles and short regrowing hair, as shown in Table 4.
3.3 |Management and outcomes of acute TE
Medications used for the management of acuteTE varied from patient to
patient as well as across different studies. Most drugs used were targeted
at hair regrowth. Minoxidil was the most common medication used in
about 40% of patients, followed by steroids (26%), and sulfur amino acid/
vitamin B6 (12.2%). Less frequently vitamin D (5%), platelet‐rich plas-
ma injections (2.5%), biotin (5%), and iron supplements (4.68%) were also
prescribed. Most patients recovered from hair loss, while a few patients
had active persistent hair fall.
27
4|DISCUSSION
While extensive research has been carried out to guide the diagnosis,
treatment, and prevention of COVID‐19, the growing evidence of
post‐recovery symptoms has prompted researchers to delve more
HUSSAIN ET AL.
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TABLE 1 Study characteristics and patient demographics
First author Study design Country of origin Sample size
Mean age
(years) and sex
(female %)
Patients with
telogen
effluvium, N(%) Comorbidities, N(%)
Previous history
of hair loss
Quality
assessment
Mieczkowska et al. Case series United States of
America
10 55/100% 10 (100) Asthma—2 (20), breast cancer–1 (10), chronic
kidney disease Stage 3–1 (10),
depression–1 (10), emphysema–1 (10),
hyperlipidemia–3 (30), PCOS–2 (20), type 2
diabetes mellitus–3 (30)
None—100% Good
Garrigues et al. Case series France 120 63.2/37.5% 24 (20) Diabetes—26 (21.7), hypertension—56 (46.7) ‐Fair
Rizzetto et al. Case series Italy 3 64.67/100% 3 (100) Autoimmune thrombocytopenia—1 (33.34),
osteoporosis—1 (33.34), diabetes mellitus—
1 (33.34), systemic hypertension—1 (33.34),
dyslipidemia—1(33.34)
AGA—1/3 Fair
Olds et al. Retrospective
study
United States of
America
10 48.5/90% 10 (100) ‐‐8 (NCOS)
Moreno‐Arrones et al. Prospective study Spain 191 47.4/78.5% 191 (100) ‐‐7 (NCOS)
Lv et al. Case report China 1 38/100% 1 (100) ‐‐Fair
Thuangtong et al. Retrospective
study
Thailand 93 40.8/41.9% 22 (23.6) Hypertension—13 (13.97), diabetes—12
(12.90), dyslipidemia—6 (6.45), allergic
rhinitis—3 (3.225), old pulmonary
tuberculosis—2 (2.15), cancer—2 (2.15),
stroke—2 (2.15),
8 (NCOS)
Abrantes et al. Retrospective
study
Multinational 30 40.5/70% 30 (100) Hypertension—1 (3.34), anxiety disorder—2
(6.67), obesity—2 (6.67), major depressive
disorder—1 (3.34), arterial hypertension—1
(3.34), hypothyroidism—2 (6.67),
dyslipidemia—1 (3.34).
AGA—8(27) 7 (NCOS)
Cline et al. Retrospective
study
United States of
America
10 ‐/100% 10 (100) Obesity—4(40), diabetes mellitus type 1—1 (10),
hyperlipidemia 4 (40), asthma 4 (40),
diabetes mellitus type 2—3 (30)
‐7 (NCOS)
Rossi et al. Case series Italy 14 47.57/78.57% 14 (100) ‐AGA—3 (21.4),
scalp
psoriasis
1 (7.14)
Fair
Saeed et al. Case series Pakistan 4 39.75/100% 4 (100) None ‐Fair
Di Landro et al. Case series Italy 39 64.6/76.9% 39 (100) ‐‐Fair
4
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HUSSAIN ET AL.

into this crucial aspect. Post‐COVID‐19 manifestations have been
described in the literature; a recent meta‐analysis reported the five
most common post‐recovery symptoms, including fatigue (58%),
headache (44%), attention disorder (27%), hair loss (25%), and dys-
pnea (24%).
31
Hair loss after recovery from COVID‐19 is a harrowing
manifestation. The current literature on acute TE occurring after re-
covery from COVID‐19 is limited to underpowered studies, which
have not been systematically appraised. We sought to fill this gap by
compiling the characteristics of 465 patients, who were diagnosed
with acute TE post‐recovery, from 19 studies originating from 10
different countries.
In alignment with our findings, acute TE was also reported during
the life‐threatening influenza pandemic of 1918–1919 (commonly
known as Spanish flu), with hair loss developing 2–6 weeks after the
onset of fever.
24,32
Moreover, we observed that acute TE occurred
around a mean duration of 74 days after the onset of COVID‐19
symptoms. This is earlier than classic acute TE, which occurs ap-
proximately 3–4 months after a triggering event. However, the tri-
choscopic and trichogram findings did not differ from classic acute
TE.
25
As shown in our results, the detailed trichoscopic findings re-
ported across the studies most commonly included reduced hair
density,
19,24,30
empty hair follicles,
9,24,25,30
short regrowing hair,
24,25
and/or hair in the telogen phase.
16,19
Similar to the findings of classic acute TE, there was a female
preponderance (67.5%) in the patients diagnosed with acute TE post‐
COVID‐19. This can be explained by the higher vulnerability of
female hair follicles, easier identification of hair loss in females owing
to longer hair, and under‐reporting in males due to the higher psy-
chological effects of hair loss in women.
24,33
Stress during COVID‐19
infection has been implicated as a potential contributor to hair
shedding.
26,27
Hypertension (27%), diabetes mellitus (17%), and dyslipidemia
(6%) were the most prevalent comorbidities in the COVID‐19 re-
covered individuals who subsequently developed acute TE. The
presence of comorbidities has been shown to increase the risk of
developing post‐COVID‐19 acute TE. In a case series of 10 patients
with COVID‐19‐associated acute TE, 9 of them had underlying co-
morbidities.
28
Similarly, Mieczkowska et al.
14
found that most (8 out
of 10) acute TE patients had pre‐existing medical conditions. How-
ever, observational studies with a larger sample size are needed to
confirm this association. Interestingly, the presence of comorbidities
increases the risk of severe COVID‐19 infection,
34
and both the
presence of comorbidities and severe COVID‐19 infection have been
associated with post‐COVID‐19 acute TE.
14,18
Our results demon-
strated that more than one‐fourth (39%) of the patients diagnosed
with acute TE post‐recovery were hospitalized during the phase of
COVID‐19 infection. Olds et al.
8
reported that 70% of the patients
with post‐COVID‐19 acute TE required hospitalization for COVID‐19
infection. Similarly, Di Landro et al.
18
noted that 16 of the 39 patients
who presented with COVID‐19‐associated acute TE had a severe
COVID‐19 infection and required hospitalization and continuous
positive airway pressure therapy. This can be attributed to the sug-
gested correlation between COVID‐19 severity and the increased
TABLE 1 (Continued)
First author Study design Country of origin Sample size
Mean age
(years) and sex
(female %)
Patients with
telogen
effluvium, N(%) Comorbidities, N(%)
Previous history
of hair loss
Quality
assessment
Starace et al. Survey‐based Multinational 67 47.5/92% 67 (66.3) ‐‐‐
Domínguez‐
Santás et al.
Case report Spain 1 42/100% 1 (100) ‐‐Fair
Deng et al. Case report United States of
America
1 41/100% 1 (100) Allergic rhinitis, diabetes mellitus,
hyperlipidemia
‐Fair
Temiz et al. Case series Turkey 8 37.25/75% 8 (100) ‐‐Fair
Arenas Soto et al. Case reports Colombia 2 36/100% 2 (100) ‐‐Fair
Roda et al. Case series Portugal 27 45/89% 27 (100) ‐‐Good
de Oliveira Izumi et al. Case study Brazil 1 34/100% 1 (100) None No Fair
Abbrreviations: AGA, androgenetic alopecia; NCOS, newcastle ottawa scale; PCOS, polycystic ovarian syndrome.
HUSSAIN ET AL.
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5

TABLE 2 Clinical features at the time of COVID‐19 infection
First author Symptoms during COVID‐19 infection, N(%)
No. of patients
hospitalized, N(%)
Hospital length
of stay Treatment for COVID‐19
Mieczkowska et al. ‐4 (40) 2.8 days Azithromycin—2, doxycycline—2, ceftriaxone—2,
hydroxychloroquine—2
Garrigues et al. Confusion—7 (5.8), cough—87 (72.5), dyspnea—88 (73.3),
myalgia—19 (15.8), diarrhea—29 (24.2), cough—20 (16.7),
chest pain—13 (10.8), fatigue—66 (55.0), dyspnea—50
(41.7), ageusia—13 (10.8), anosmia—16 (13.3), hair loss—24
(20.0), attention disorder—32 (26.7), memory loss—41
(34.2), sleep disorder—37 (30.8)
24 (100) 11.2 days ‐
Rizzetto et al. Bilateral interstitial pneumonia—(100), distress respiratory
syndrome—(66.7), diarrhea—(33.34), diffuse itching and
flushing—(33.34), weight loss—(33.34)
3 (100) 27 days Enoxaparin—3, ceftriaxone—1, tocilizumab—1, lopinavir/ritonavir—2,
gliclazide—1, acarbose—1, ezetimibe/simvastatin—1, sitagliptin—
1, chlorphenamine maleate—1
Olds et al. ‐10 (100) ‐Azithromycin—4/10 (49), antibiotics—2/10 (20), ceftriaxone—1/10
(10), hydroxychloroquine—4/10 (40), methylprednisolone—3/10
(30), supportive—2/10(20), prednisone—1/10 (10)
Moreno‐Arrones et al. Fever—165 (86.4), dermatologic manifestations—23 (12) 55 (28.8) ‐Paracetamol—144 (75.4), NSAIDs—28 (14.7), oral corticosteroids—50
(26.2), oral antibiotics—82 (42.9), lopinavir/ritonavir—38 (19.9),
remdesivir—10 (5.2), tocilizumab—26 (13.54), enoxaparin—
97 (50.5)
Lv et al. Trichodynia, oily scalp 13 days ‐
Thuangtong et al. Asymptomatic—1/93 (1.0), upper respiratory tract—66/93
(71.0), lower respiratory tract—26/93 (28.0), urticaria—2/
93(2.15), maculopapular rash—2/93 (2.15)
93 (100) 6 days ‐
Abrantes et al. ‐1 (3.34) ‐‐
Cline et al. ‐‐‐‐
Rossi et al. Defluvium—14/14 (100), itching—2/14(14.28), eyelid edema—
1/14 (7.14)
4 (28.57) ‐Tocilizumab—2/14 (14.28), paracetamol—7/14 (50),
hydroxychloroquine—2/14 (14.28), other antibiotics—3/14
(21.43), azithromycin—3/14 (21.428), steroids—1/14 (7.14),
levofloxacin—1/14 (7.14), darunavir + cobicistat—1/14 (7.142),
pantoprazole—1/14 (7.142)
Saeed et al. Diarrhea—2 (50), loss of taste and smell—1 (25) 0 0 Zinc—1 (25), vitamin C—1 (25), calcium—1 (25), vitamin D—1 (25)
Di Landro et al. Trichodynia (18), anosmia aguesia (66.6) 16 (41) ‐Paracetamol—39 (100), systemic steroids—25 (64), anticoagulants—
16 (41)
6
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risk of subsequent acute TE, as patients with severe COVID‐19 in-
fection have higher levels of pro‐inflammatory cytokines.
8
However,
this does not imply that acute TE does not occur in patients with
subclinical COVID‐19 infection. In a multicenter study of 214 cases
of COVID‐19 associated acute TE, Moreno‐Arrones et al.
29
observed
that approximately 1 out of 10 patients had subclinical COVID‐19
infection. Therefore, it is imperative for clinicians to consider a prior
history of COVID‐19 infection, regardless of the severity, as a dif-
ferential diagnosis in every patient consulting for acute TE in the
context of the pandemic.
9,29
The correlation between the severity of
COVID‐19 infection and the intensity of acute TE remains unclear.
According to Rossi et al.,
25
all four patients who required hospitali-
zation during COVID‐19 infection had a regression in acute TE
around 3–5 months after the onset of hair fall, suggesting no asso-
ciation between the severity of COVID‐19 infection and the severity
of subsequent acute TE.
In COVID‐19 patients, the pathophysiology behind acute TE is
poorly understood, with numerous suggested mechanisms. According
to the existing literature, the following pathological pathways have
been proposed:
1. Elevated levels of interleukin‐6, a pro‐inflammatory cytokine,
were observed in COVID‐19 patients.
25
Interleukin‐6 inhibits the
elongation of the hair shaft by suppressing the proliferation of matrix
cells in cultured hair follicles.
9
2. Interferon is well‐recognized to induce acute TE. Elevated le-
vels of interferon are documented in COVID‐19 and other viral ill-
nesses as a part of the body's antiviral response.
25
3. Metalloproteinases 1 and 3 and interleukin‐1βmay inhibit the
growth of hair follicles.
25
4. COVID‐19 infection causes the activation of the coagulation
cascade, which subsequently decreases the concentration of
anticoagulation proteins due to diminished production and in-
creased consumption. Moreover, these factors may result in
microthrombi formation, which may occlude the blood supply of
hair follicles.
8,27
5. In COVID‐19 patients, non‐neutralizing virus‐specific anti-
bodies interact with Fcγand/or complement receptors, facilitating
the entry of the virus into the host cells. This may lead to direct
damage to the hair follicles by the virus. The entry of the pathogen
into the host cells via this antibody‐dependent enhancement, which
led to hair fall, was documented in some infected patients in the
2014–2015 dengue epidemic.
25
6. Medications used during COVID‐19 treatment may have
contributed to acute TE.
8,27
However, there is conflicting evidence
regarding their potential pathways. According to Rossi et al.
25
and
Rizzetto et al.,
30
drug‐induced acute TE in COVID‐19 patients was
quite unlikely due to the early onset of acute TE and the short
duration of treatment for COVID‐19, respectively.
The management of acute TE associated with COVID‐19 varied
across the studies. Lv et al.
16
described the case of a 38‐year‐old
female with post‐COVID‐19 acute TE who was successfully treated
with topical 5% minoxidil mixed with halcinonide solution as well as
selenium sulfide lotion mixed with shampoo. In a case series of
TABLE 2 (Continued)
First author Symptoms during COVID‐19 infection, N(%)
No. of patients
hospitalized, N(%)
Hospital length
of stay Treatment for COVID‐19
Starace et al. Fever—(75.2), cough—(53.5), ageusia—(41.6), anosmia—(57.4),
diarrhea—(5.9), myalgia—(10.9), ooryza—(9.9), headache—
(23.8), dyspnea—(7.9), asthenia—(28.7)
‐‐‐
Domínguez‐Santás et al. Coughing, fever 0 0 ‐
Deng et al. Acral desquamation of fingers and palms, perniosis, beau lines
on fingers
0 0 Ibuprofen—1 (100), antitussive—1 (100)
Temiz et al. ‐‐‐‐
Arenas Soto et al. None 0 0 ‐
Roda et al. Trichodynia—5 (18.5), fever—17 (63), ageusia—8 (30), cough—
6(22), myalgia—5 (18.5), anosmia—4 (15), thoracalgia—3
(11), asymptomatic—4 (15), pernio lesions—1 (3.7),
maculopapular eruption—1 (3.7)
3 (11) ‐‐
de Oliveira Izumi et al. ‐‐‐‐
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TABLE 3 Clinical findings of TE observed in COVID‐19 recovered patients
First author
Duration after
recovery
Mean time from
COVID‐19 symptom
onset Physical exam findings Treatment of TE, N(%) Outcome of alopecia
Mieczkowska et al. ‐114 days Positive hair pull test with many telogen hair,
pronounced thinning—1 patient; global loss of hair
volume—1 patient, areas of lower hair density with
many vellus hair on bilateral frontotemporal regions
—1 patient
‐Resolution
Garrigues et al. 110 days 110.9 days ‐‐Resolution
Rizzetto et al. 57 days 90 days Positive pull test positive—3 patients Oral supplementation with sulfur amino acid/vitamin
B6—3 (100), peptide mimicking hair growth factor
lotion—3 (100), minoxidil 5% lotion—1 (33.34%)
‐
Olds et al. ‐50 days Positive telogen hair pull test—4 (40%), negative telogen
hair pull test—2 (20%), diffuse hair thinning—4 (40%),
postinflammatory hyperpigmentation—1(10%),
thinning of frontal scalp and vertex—1 (10%),
miniaturization at crown—1 (10%)
Triamcinolone lotion for itching—1 (10), minoxidil 5%
solution—4 (40), minoxidil 5% foam—1 (10), biotin
supplementation—1 (10), iron supplementation—1
(10), dandruff shampoo—1 (10), clobetasol solution
—1 (10)
Resolution
Moreno‐Arrones et al. ‐57.1 days Absence of anisotrichosis and presence of
regrowing hair
2% topical minoxidil—32 (26.8), 5% topical minoxidil—
45 (23.6), oral minoxidil—18 (9.3), oral
nutricosmetics—70 (36.4), PRP injections—8 (4), no
treatment—18 (9.4)
‐
Lv et al. 72 days 83 days Positive pull test (whole head) Topical 5% minoxidil, halcinonide lotion, selenium
sulfide lotion
Resolution
Thuangtong et al. 42 days 12 days Increased hair shedding ‐Resolution
Abrantes 34 days 45 days Positive hair pull test grading—1, grading—1 (3.34%), 2—
13 (43.34%), 3—826.67%), 4—8 (26.67%)
‐Resolution
Cline et al. ‐‐ ‐ ‐ ‐
Rossi et al. ‐60 days Hair pull test positive—(50) Alpha‐lipoic acid, calcium pantothenate (vitamin B5),
vitamin D3, ferrous gluconate, clobetasol
propionate 0.05% foam—14 (100)
Resolution
Saeed et al. ‐‐ Positive hair pull test—4 (100) ‐‐
Di Landro et al. 72 days 63 days Positive hair pull test—39 (100), empty follicular ostia
and telogen club hair—3 (16.67)
N/m Resolution
8
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HUSSAIN ET AL.

10 patients conducted by Olds et al.,
8
topical minoxidil was pre-
scribed in half of the patients, while no treatment was provided to
three patients. In all three cases of post‐COVID‐19 acute TE pre-
sented by Rizzetto et al.,
30
oral supplementation with sulfur amino
acid/vitamin B6 as well as peptide mimicking hair growth factor lo-
tion were used to treat acute TE, while topical minoxidil was given to
only one patient who was suffering from androgenetic alopecia.
Minoxidil was not given to the rest of the two acute TE patients as it
could have increased the hair fall initially, due to the reduced telogen
phase and the early entry of the resting follicles into the anagen
phase. The efficacy of minoxidil for treating post‐COVID‐19 acute TE
has not been established.
8
This warrants randomized controlled trials
and prospective studies to fill this gap.
Acute TE is self‐limited and undergoes remission within 3–6
months of onset unless associated with androgenetic alopecia.
27
In
concordance with the findings of acute TE caused by other etiologies,
post‐COVID‐19 acute TE also resolved in most patients, as shown in
Table 3. Through this article, we highlight the importance of an in-
creased familiarity of clinicians with post‐COVID‐19 acute TE to
provide appropriate counseling and treatment. It is imperative to
recognize that TE is a stressful situation for most patients, especially
females. Identifying COVID‐19 infection as a potential cause of acute
TE will help the clinicians counsel the patients that after recovery
from COVID‐19, the factor triggering acute TE has been resolved.
Educating the patients about the transient nature of the condition is
essential to alleviate their stress. Patients should be advised to ensure
a healthy diet and informed that it may take up to 18 months for the
hair thickness to return to the baseline.
8
4.1 |Limitations
There are a few limitations in this systematic review that must be
taken into account. First, these reports are underpowered as many
cases of acute TE go unreported, and hence, the findings may not be
decisive and relevant to the entire population. This calls for further
large‐scale studies addressing the clinical characteristics and possible
pathological mechanisms of post‐COVID‐19 acute TE. Second, most
of the studies were case series that described patients selected for
inclusion because they had acute TE and therefore the incidence and
prevalence of this complication post‐COVID‐19 cannot be de-
termined. Evaluation of the incidence of acute TE in COVID‐19 sur-
vivors mandates large prospective studies. Third, although COVID‐19
has been established as the main trigger for acute TE, other factors,
including poor nutrition, deteriorating scalp health, infrequent
shampooing, and medications such as anticoagulants, may be po-
tential contributors. Moreover, the emotional toll of the COVID‐19
pandemic on the mental health, of even the noninfected individuals,
may be an inciting factor for acute TE. Last, another limitation was
that we could not register the review. We tried to prospectively
register our review, but decided to go against it as it was taking an
unreasonably longer time than expected due to the increased pool of
COVID‐19‐related articles.
TABLE 3 (Continued)
First author
Duration after
recovery
Mean time from
COVID‐19 symptom
onset Physical exam findings Treatment of TE, N(%) Outcome of alopecia
Starace et al. ‐84 days ‐High‐potency topical steroids—(50), supplements with
amino acids and vitamin B complex—(27), topical
minoxidil—(15), pain relief lotions or hair growth
promoters—(10)
Resolution—91 (90),
active persistent—
10 (10)
Domínguez‐Santás et al. ‐120 days Positive hair pull test Reassurance ‐
Deng et al. 81 days 60 days ‐‐Resolution
Temiz et al. ‐81.9 days ‐‐Resolution
Arenas Soto et al. ‐‐ Positive hair pull test—2 (100), increase in the
percentage of villous hair—(50)
Oral sulfur amino acids—1 (50), Vitamin B6—1 (50),
topical 5% minoxidil—1 (50), 0.5% biotin—1 (50)
‐
Roda et al. ‐70 days Positive pull test ‐Resolution—16 (59%)
de Oliveira Izumi et al. ‐90 days Positive hair pull test, area of diffuse capillary thinning Topical 5% minoxidil Partial resolution
Abbreviations: PRP, platelet‐rich plasma; TE, telogen effluvium.
HUSSAIN ET AL.
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9

5|CONCLUSIONS
In this article, we systematically reviewed the existing literature on
acute TE occurring after recovery from COVID‐19. Post‐COVID‐19
acute TE occurred earlier than classic acute TE, but showed similar
trichogram and trichoscopic findings, including reduced hair density,
empty hair follicles, and/or short regrowing hair. Although our results
did not suggest COVID‐19 to be the absolute cause of acute TE, they
highlight the need to consider the possibility of post‐COVID‐19 acute
TE in a patient presenting with hair fall, with a history of COVID‐19
infection, in the context of COVID‐19 pandemic. Although acute TE is
a transient condition, it can negatively impact the mental health of
individuals who have already suffered from the debilitating COVID‐
19 illness. Identifying COVID‐19 infection as a potential cause of
acute TE will help the clinicians counsel the patients, relieving them
from undue stress.
ACKNOWLEDGMENT
This research did not receive any specific grant from funding agencies
in the public, commercial, or not‐for‐profit sectors.
CONFLICT OF INTERESTS
The authors declare that there are no conflict of interests.
AUTHOR CONTRIBUTIONS
Conceptualization, writing—reviewing and editing:NabeelHussain.
Conceptualization, writing—original draft: Preeti Agarwala. Con-
ceptualization, writing—reviewing and editing: Kinza Iqbal. Data
curation, writing—reviewing and editing: Hanaa Mohamed Sheikh
Omar. Data curation, formal analysis: Gurusha Jangid. Data cura-
tion, writing—original draft:VrajPatel.Writing—original draft,
writing—reviewing and editing: Sawai Singh Rathore. Data curation,
methodology: Chandani Kumari. Writing—original draft:Felipe
Velasquez‐Botero. Formal analysis, supervision: Guadalupe Abigail
Benítez López. Data curation, methodology:YogeshVishwakarma.
Formal analysis, supervision: Airin Parvin Nipu. Data curation, su-
pervision:NomanKhurshidAhmed.
DATA AVAILABILITY STATEMENT
Data sharing is not applicable to this article as no new data were
created or analyzed in this study.
ORCID
Sawai Singh Rathore http://orcid.org/0000-0003-1954-094X
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How to cite this article: Hussain N, Agarwala P, Iqbal K, et al.
A systematic review of acute telogen effluvium, a harrowing
post‐COVID‐19 manifestation. J Med Virol. 2021;1‐11.
doi:10.1002/jmv.27534
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