Dermatology: Practical and Conceptual


Original Article | Dermatol Pract Concept. 2023;13(1):e2023060 1

The Relationship Between ABO and Rh Blood 
Groups with Alopecia Areata

Farzaneh Shirazi1, Safoura Shakoei2, Maryam Nasimi3, Zahra Saffarian2, Robabeh Abedini3

1 School of medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran

2 Department of Dermatology, Imam Khomeini Hospital, Tehran University of Medical Sciences (TUMS), Tehran, Iran

3 Department of Dermatology, Razi Hospital, Tehran University of Medical Sciences (TUMS), Tehran, Iran

Key words: alopecia areata, blood group, ABO, Rh

Citation: Shirazi F, Shakoei S, Nasimi M, Abedini R. The relationship between ABO and Rh blood groups with alopecia areata. Dermatol 
Pract Concept. 2023;13(1):e2023060. DOI: https://doi.org/10.5826/dpc.1301a60

Accepted: April 28, 2022; Published: January 2023

Copyright: ©2023 Shirazi et al. This is an open-access article distributed under the terms of the Creative Commons Attribution-
NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, 
distribution, and reproduction in any medium, provided the original authors and source are credited.

Funding: It is financially supported by the vice-chancellor of research affairs of the Tehran University of Medical Sciences.

Competing Interests: None.

Authorship: All authors have contributed significantly to this publication

Corresponding Author: Safoura Shakoei MD, Department of Dermatology, Imam Khomeini Hospital, Tehran University of Medical 

Sciences (TUMS), Tehran, Iran. Tel: 00982161192655 Fax: 00982188046767 Email: dr.shakoei@gmail.com

Introduction: Alopecia areata (AA) is a common non-scaring hair loss disease. Genetic susceptibility 
and environmental factors can develop the disease.

Objectives: We investigated the association between AA and ABO and Rh blood groups.

Methods:  This cross-sectional study was done on 200 patients with AA and 200 healthy controls 
(HCs) between March 2021 and September 2021.

Results: The prevalence of blood groups O, A, B, and AB in patients with AA was 30%, 30.5%, 
10.5%, and 29%, respectively. A significant difference was detected between the two groups in the fre-
quency of the ABO and ABO*Rh blood groups (p-value < 0.05). Compared to the HCs, the prevalence 
of the AB and AB+ blood group was higher in AA patients. No significant relationship was detected 
between sex, BMI, duration of disease, age at onset, severity of alopecia tool (SALT) score, hair loss 
pattern, and nail involvement with ABO and Rh blood groups (p-value > 0.05).

Conclusion: In conclusion, the highest difference was related to the AB+ blood group, so compared 
to HCs, the AB+ blood group frequency was higher in patients with AA. However, more studies with 
larger sample sizes on different ethnicities should be performed to verify the results of this study.

ABSTRACT



2 Original Article | Dermatol Pract Concept. 2023;13(1):e2023060

Introduction

Alopecia areata (AA) is a common non-scaring hair loss 

disorder. The prevalence of the disease is 1 in 1000 cases 

and has a lifetime incidence of 2% [1]. The prevalence of 

the disorders indicated above is expected to be roughly 0.2 

percent in the overall population. Moreover, genetic suscep-

tibility and environmental factors can also induce the disease 

to develop [2]. However, the specific cause of the disease is 

unidentified. There are several lines of evidence linking AA 

to autoimmune diseases, like type 1 diabetes mellitus (DM), 

rheumatoid arthritis (RA), systemic lupus erythematosus 

(SLE), vitiligo, and pemphigus Vulgaris [3-6].

Human gene variation, such as HLA systems, is defined 

by red cell isoenzymes, blood groups, hemoglobin varia-

tions, and serum proteins [7]. The ABO blood group system 

includes four O, A, B, and AB common blood groups. The 

presence of specific carbohydrate sugars on the surface of 

red blood cells distinguishes these different blood groups. A 

is identified by N-acetylgalactosamine, and B is identified as 

D-galactose for the B antigen. These sugars can be built on 

the H antigen, and in cases of the unmodified H antigen, the 

blood group will be O since the A and B antigens are unable 

to adhere to the surface of red blood cells [7]. The Rhesus 

blood group system is composed of Rhesus monkey erythro-

cyte antigens like the D antigen that can be found on the red 

cells of most Rh+ humans. This system is highly complicated, 

and some Rh alloantigens have yet to be biochemically de-

scribed [8]. Because blood types are unaffected by environ-

mental factors, they are a useful and essential resource in the 

pathogenesis of diseases. In this regard, many investigations 

have been conducted to study the relationship between can-

cer types, blood types, and other disorders [9].

Objectives

Also, some case series demonstrated substantial connections 

between blood groups and autoimmune disorders like multi-

ple sclerosis, psoriasis, and pemphigus [10-12]. However, the 

exact nature of the linkage between blood groups and AA is 

not identified. Thus, we investigated the association between 

AA and ABO, and Rh systems.

Methods

The current cross-sectional study investigated the associa-

tion between AA and ABO/Rh blood groups. The study was 

conducted on 200 cases with AA and 200 healthy controls 

(HCs) that attended our dermatology clinic in Hospitals be-

tween March 2021 and September 2021. Participants with 

other autoimmune and systemic disorders were excluded. 

The patients referred to the AA clinic were enrolled in the 

study and our healthy control objects were selected among 

people who did not have known systemic and skin disorders 

and were often referred for cosmetic problems. We matched 

age and sex between the two groups.

We followed the principles of the Helsinki Declaration. 

The Institutional Review Board of our university approved 

the protocol of this study. Informed consent was attained 

from all participants.

Statistical Analysis

SPSS version 20 (IBM Company, USA) was applied to an-

alyze the variables. Continuous variables are displayed as 

mean (standard deviation), and categorical variables are re-

ported as frequency (percentage). Student T-test (two-tailed) 

was applied for the comparison of continuous variables. The 

Chi-square or Fisher’s exact test was employed for the com-

parison of the categorical variables between the two study 

groups. A P-value <0.05 was regarded as significant.

Results

Baseline Characteristics of Participants

Two hundred patients with AA and 200 HCs were included. 

The baseline characteristics of the subjects in the AA and HC 

groups are detailed in Table 1. The two study groups were 

comparable in terms of age, sex, and BMI.

Of 200 AA patients, 81 patients had patchy hair loss, 80 

had Universalis hair loss, 35 had  Totalis hair loss, and 3 had 

Ophiasis hair loss. Nail involvement was seen in 51 patients 

to some degree and in 19 patients as dystrophy (Table 1).

Comparison of Blood Groups Between AA Patients 
and HCs

Table 2 indicates the frequency of different types of blood 

groups in AA patients and HCs. ABO blood groups were 

significantly different between study groups (p=0.001). In 

this regard, the AA group showed a higher prevalence of 

the AB blood group, while the prevalence of the O, A, and 

B blood groups was higher in HCs (p=0.001). Nonetheless, 

no significant between-group differences were found based 

on O/non-O (p=0.391) and Rh (p=0.605) blood groups. 

Finally, ABO*Rh blood groups were significantly differ-

ent between study groups (p=0.017). The most difference 

was related to the AB+ blood group, whose frequency was 

markedly higher in patients with AA compared to HCs 

(Table 2).

Association Between Blood Groups and Clinical 
Characteristics in Patients with AA

According to Table 3, no significant association was detected 

between sex, BMI, disease duration, age of onset, SALT 



Original Article | Dermatol Pract Concept. 2023;13(1):e2023060 3

Table 1. Baseline characteristics of the patients in AA and HC groups.

AA group 
(n=200)

HC group 
(n=200) P-value

Age [years; mean (SD)] 33.26 (14.33) 33.73 (12.05) 0.726a

Sex [n (%)] 0.468b

• Male 77 (38.5%) 70 (35%)

• Female 123 (61.5%) 130 (65%)

BMI [kg/m2; mean (SD)] 25.87 (17.86) 26.06 (23.11) 0.926a

Disease duration [years; mean (SD)] 8.56 (8.04)

Age of onset [years; mean (SD)] 23.15 (12.94)

Current episode [months; mean (SD)] 8.25 (7.71)

SALT score  [mean (SD)] 75.68 (29.93)

The pattern of hair loss

• Patchy 81 (40.6)

• Universalis 80 (40%)

• Totalis 35 (17.6%)

• Ophiasis 3 (1.6%)

Nail involvement

• None 129 (64.6%)

• Some 51 (25.6%)

• Dystrophy 19 (9.6%)

A P-value of < 0.05 was considered statistically significant.
SD: standard deviation
a Student T-test
b Chi-square test

Table 2. Comparison of different types of blood groups between AA and Healthy control group groups.

AA group 
(n=200)

HC group 
(n=200) P-value

ABO [n (%)] 0.001a

• O 60 (30%) 68 (34%)

• A 61 (30.5%) 79 (39.5%)

• B 21 (10.5%) 28 (14%)

• AB 58 (29%) 25 (12.5%)

Rh [n (%)] 0.605a

• Negative 17 (8.5%) 20 (10%)

• Positive 183 (91.5%) 180 (90%)

ABO*Rh [n (%)] 0.017b

• O- 9 (4.5%) 10 (5%)

• A- 3 (1.5%) 5 (2.5%)

• B- 3 (1.5%) 4 (3%)

• AB- 2 (1%) 1 (0.5%)

• O+ 51 (25.5%) 58 (29%)

• A+ 58 (29%) 74 (37%)

• B+ 18 (9%) 24 (12%)

• AB+ 56 (28%) 24 (12%)

HC: Healthy control. A P-value of < 0.05 was considered statistically significant.
a Chi-square test
b Fisher exact test



4 Original Article | Dermatol Pract Concept. 2023;13(1):e2023060

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Original Article | Dermatol Pract Concept. 2023;13(1):e2023060 5

the association between alopecia areata and ABO and Rh 

blood groups. They indicated a similar distribution of the 

ABO blood group in the patient and healthy groups. How-

ever, the Rh+ blood group was markedly higher in the 

healthy group than the patient group. Also, Rather et al. [24] 

conducted a case-control study in Kashmir to examine the 

relationship between ABO blood groups and different skin 

diseases (psoriasis, vitiligo, AA, pemphigus Vulgaris). Also, 

37.1% of patients with psoriasis showed O blood group, 

followed by type B (30%) and A (25.7%), with no signifi-

cant differences between study groups. In cases with vitiligo, 

47.4% showed the B blood group, followed by blood groups 

O (36.8%) and A (10.5%). The frequency of A and B blood 

groups was significantly different between vitiligo patients 

and controls. In AA patients, blood group B was detected 

in 45.2% of patients, and groups O (28.6%) and A (19%) 

ranked second and third, with no significant differences be-

tween study groups. In patients with pemphigus Vulgaris, 

40% of patients showed O and B blood groups, followed 

by blood group A (20%), with no significant differences be-

tween the groups. Contrary to the results of these studies, 

a significant difference was found between the two groups 

in our study. The highest difference was related to the AB+ 

blood group, so compared to the control group, patients with 

AA belonged to the AB blood group with higher frequency. 

We also examined the relationship between the characteris-

tics of AA and the frequency of ABO and Rh blood groups; 

no significant association was detected between ABO or Rh 

blood groups and sex, BMI, disease duration, age of onset, 

SALT score, hair loss pattern, and nail involvement in pa-

tients with AA.

Conclusion

A significant difference was found between the two groups 

regarding the frequency of the ABO*Rh blood group. The 

frequency of the AB+ blood group was higher in patients 

with AA. Further studies could verify the results of this study.

References

1. Villasante Fricke AC, Miteva M. Epidemiology and burden of 

alopecia areata: a systematic review. Clinical, cosmetic and in-

vestigational dermatology. 2015;8:397-403. doi:10.2147/ccid.

S53985

2. Sterkens A, Lambert J, Bervoets A. Alopecia areata: a review on di-

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doi:10.1007/s10238-020-00673-w

3. Chang Y-J, Lee Y-H, Leong P-Y, Wang Y-H, Wei JC-C. 

 Impact of Rheumatoid Arthritis on Alopecia: A Nationwide 

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score, patterns of hair loss, nail involvement, and ABO/Rh 

blood groups in patients with AA (p>0.05).

Discussion

We assessed the relationship between AA and ABO and Rh 

blood groups. The prevalence of blood groups O, A, B, and 

AB in patients with AA was 30%, 30.5%, 10.5%, and 29%, 

respectively. A significant difference was detected between 

the two study groups regarding the frequency of the ABO 

blood group. The highest difference was related to the AB 

blood group, so compared to HCs, patients with AA showed 

a higher frequency of the AB blood group. The highest dif-

ference was related to the AB+ blood group, so compared 

to HCs, patients with AA showed a higher frequency of the 

AB+ blood group.

AA is a recurrent inflammatory disorder that affects peo-

ple of all ages and genders. Despite the disease’s importance, 

the specific etiology has yet to be fully understood. The ABO 

blood group family antigens have long been identified. Blood 

group alloantigens can be found on the membrane of epithe-

lial cells and red blood cells. There is a link between blood 

types and various dermatologic conditions [9, 13, 14], lead-

ing to the elucidation of disease pathogenesis. For instance, 

malignant melanoma was found to have a statistically sig-

nificant higher risk in patients with the O blood group [9].  

Several previous reports have linked certain infections to spe-

cific ABO blood groups [15]. Tuberculoid leprosy is linked 

to the O blood group, while lepromatous leprosy is linked to 

the A and B blood groups, gonorrhea to the B blood group, 

smallpox to the A and B blood groups, and Escherichia coli 

O 157 infection to the O blood type [16]. Many studies 

have investigated the association between blood groups and 

autoimmune disorders like pemphigus Vulgaris, DM, RA, 

spondyloarthropathy, vasculitis,  Behcet’s disease, SLE, sys-

temic sclerosis, and Sjogren’s syndrome [10,17, 18]. Among 

these, no link was found between the ABO blood types and 

pemphigus Vulgaris, which is a well-known autoimmune 

skin disorder [18, 19]. In the etiopathogenesis of AA, au-

toimmunity is more prominent.   Different researchers have 

established the relevance of T cells in the disease [20]. How-

ever, genetic variables play a role in illness susceptibility and 

severity as well. In single-twin investigations, the frequency 

of concurrent disease was found to be 55 percent, indicat-

ing that genetic and environmental variables play a role in 

the disease’s development [20, 21]. The genes that code for 

blood group antigens are found on chromosome 9q34.2 (for 

the ABO blood group) and chromosome 1p36.11 (for the Rh 

blood group) [22].

Up to now, only two investigations have examined the 

relationship between blood type and AA. In 2018,  İslamoğlu 
et al. [23] conducted a clinical study in Turkey to investigate 



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the American Academy of Dermatology. Jul 2004;51(1  Suppl): 

S16-7. doi:10.1016/j.jaad.2004.01.013

21. Martinez-Mir A, Zlotogorski A, Ott J, Gordon D, Christiano 

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22. Mouhari-Toure A, Saka B, Kombaté K, et al. Is There an Associ-

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ABO blood types in various dermatoses in Kashmiri population: 

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