Ant‐induced alopecia: A new differential diagnosis for nonscarring alopecia

Abstract

Ant‐induced alopecia is a rare condition caused by Pheidole pallidula species. This particular cause of nonscaring alopecia should be considered a new differential diagnosis.

Ant‐induced alopecia is a rare condition caused by Pheidole pallidula species. This particular cause of nonscaring alopecia should be considered a new differential diagnosis.

1. INTRODUCTION

Ant‐induced alopecia is a rare condition; however, due to the increasing number of affected cases, this cause of nonscaring alopecia should be considered a new differential diagnosis. This article presents a case of ant‐induced alopecia.

Hair is a part of the body with a bold cosmetic aspect that affects people's life.¹ Some studies have shown the association of alopecia with psychological disorders such as depression and anxiety; therefore, physicians should consider this condition more than a cosmetic disorder.², ³ Different types of alopecia are categorized into two groups, including nonscaring and scaring alopecia. Various conditions can cause nonscaring alopecia, ranging from infections such as tinea capitis to autoimmune conditions like alopecia areata.⁴ An ant species called Pheidole pallidula (P. pallidula) has also been shown to cause hair loss in some parts of the head in some cases.⁵ This study reports on an Iranian woman with a case of ant‐induced alopecia.

1.1. Case presentation

A 45‐year‐old woman was admitted to Shahrekord University of Medical Sciences’ dermatology clinic with a sudden hair loss that had occurred overnight. She had no history of any specific diseases or medication consumption. Moreover, she had taken a trip from Isfahan to Shahrekord the day before and this incident had taken place in her mother‐in‐law's house.

In the examination, there were multiple nonscarring, nearly round patches of alopecia with a diameter of 1–2 cm in the vertex, which was nonexistent in the other regions, and no signs of scaling, erythema, and inflammation were observed in her skin.

The caliber, fragility, and shape of the hair were normal, and there was no exclamation mark hair. In addition, the alopecic patches were rough to touch and the hair looked cut to the same length about a few millimeters above the hair shaft (Figure 1) and parts of a dead ant were found in the patient's hair. The pull test was also negative for this case. There were no erythema, scaling, and crusting in the hair loss areas. The patient had no history of any psychiatric disturbances, and there was no broken hair in different sizes on her head. Based on her history and physical examinations, the patient was diagnosed with ant‐induced alopecia. The patient was sent home with reassurance and no treatments. She was advised to bring with her a sample of the ants, if possible, to be sent to the entomology laboratory.

FIGURE 1.

Short hairs that has been cut a few millimeters above the surface of the skin

1.2. Outcome and follow‐up

Three weeks after her discharge from the clinic, she came for her follow‐up with her mother‐in‐law, and her alopecic regions seemed to have been cured and she had brought some of the responsible ants with her (Figure 2). The ants were sent to the entomology laboratory and were then identified as the P. pallidula sp. Her mother‐in‐law had not experienced the same incident ever in her life.

FIGURE 2.

Ants brought by the patient

2. DISCUSSION

There are many reasons for hair loss in women, thus necessitating thorough history‐taking and physical examinations.⁴ In general, the causes of hair loss can be categorized into two groups, such as scaring and nonscaring alopecia.⁶ Physical examination, history‐taking, and some other para‐clinical tests can help physicians differentiate between the causes of this health condition, including infectious (including tinea capitis) and psychiatric (including trichotillomania) causes, autoimmune reasons (such as alopecia areata), and other metabolic diseases or malnutrition. Moreover, healthcare providers should know the pathophysiology of this condition in different age‐groups, since having a thorough understanding of the various causes of hair loss is crucial for its management.⁴, ⁷ Besides these frequent causes, there are some other rare causes that could induce alopecia, such as arthropod bite reactions.⁸

Ant‐induced hair loss was first described by Radmanesh et al.⁹ in 1999, who reported three cases of ant‐induced alopecia in Ahwaz, Iran. Afterward, some additional cases were also reported, as summarized in Table 1. All the cases of ant‐induced alopecia were due to the genus P. pallidula (Table 1).

TABLE 1.

Ant‐induced alopecia cases reported around the world

Report	Region	Age/sex	Area	Distribution	Other signs and symptoms	Skin and hair characteristic	Ant spp.
Present report	Shahrekord/Iran	45/F	scalp	1–2‐cm patchy alopecic reigns in vertex	mild pruritus	greasy scalps	Pheidole genus
Namazi et al.17	Shiraz/Iran	35/M	scalp	3 × 3.5‐cm area on the right vertex	tiny erythematous macules	greasy scalps	Pheidole genus
Razmyar et al.18	Mashhad/Iran	34/M	scalp	3 × 4‐cm alopecic patch on the vertex	Not anything	N/M	Pheidole genus
Mortazavi et al19	Mazandaran/Iran	29/M	scalp	nearly round area of alopecia at the vertex	Not anything	mild androgenetic alopecia (grade III)	Pheidole genus
	Mazandaran/Iran	25/F	scalp	large, linear area of hair loss at the vertex	Not anything	mild seborrheic dermatitis	Pheidole genus
Shamsadini et al.20	Kerman/Iran	18/M	scalp	3.5 × 3.5‐cm on the right side of the vertex	mild erythema and mild pruritus	n/m	Pheidole genus
	Kerman/Iran	21/F	n/m	n/m	pruritus that needs diphenhydramine lotion	n/m	Pheidole genus
Radmanesh et al.21	Ahwaz and Behbahan/Iran	13 M and 3 F	scalp	n/m	Mild erythema and signs of screeching in some	n/m	Pheidole genus
Veraldi et al.22	Milan/Italya	14/M	scalp	3.5‐cm on the vertex	mild pruritus	n/m	Pheidole genus
Kapdağli et a.l23	Adana/Turkey	5/F	scalp	3 × 4‐cm on the vertex	Not anything	Normal scalp skin	Pheidole genus
Feily et al.24	Jahrom/Iran	18/M	scalp	alopecia with a vertical linear distribution on occiput	Not anything	Normal scalp skin	Probably Pheidole genus
Aghaei et al.25	Shiraz/Iran	32/F	scalp	the circular patch of alopecia on the vertex	Several red macules	Normal scalp skin	Probably Pheidole genus

Abbreviations: F, female; M, male; n/m, not mentioned; spp, Species.

^a The reported case had a trip to Iran.

P. pallidula (barber ants) has been reported to cause such types of alopecia, mainly in Iran, but there have been two reported cases in Turkey and Italy as well, one of whom had taken a trip to Iran. It thus seems that this species is becoming more and more dominant in some regions, such as across the Mediterranean countries and in tropical and subtropical regions.¹⁰, ¹¹

Several hypotheses can explain the development of this condition, including the following: First, similarities between the pheromones in P. pallidula and some chemicals in the sebaceous glands and skin of some humans¹⁰; second, the infection of P. pallidula with some parasites causes neural shock and seizure‐like behaviors in ants, which cause the ants to attack the hair. In a similar study, Lefebvre showed that parasitic infection causes behavioral changes in P. dentate ¹² and results in specific gene mutations in some ants of the P. pallidula sp. that may cause the ants to attack the hair. In addition, studies on the behavior of P. pallidula ants have shown that their behavioral changes following environmental changes are based on gene expression switch¹³, ¹⁴, ¹⁵; however, further studies are needed to identify the exact cause or causes of this behavior in ants.

In this type of hair loss, the patient complains of sudden hair loss with no history of other diseases and is concerned about having their hair cut short on a certain area of their scalp, usually forming an irregular patch with no scaling or crusting. The diagnosis of this type of alopecia is mainly performed by ruling out the other conditions.⁵

Our patient had no erythema, scaling, and crusting related to tinea capitis on her scalp lesions. There were also no signs of alopecia areata and trichotillomania in her¹⁶; therefore, they were ruled out from the diagnosis.

The patient's mother‐in‐law had not experienced the same condition even though she had had greater exposure to these ants, making the etiology of this phenomenon more interesting. One possible reason may be the difference in skin greasiness, as our case had greasy scalps while her mother‐in‐law did not. Studies have shown that this species is lipophilic and more inclined to attack greasy scalps.⁵

3. CONCLUSION

Ant‐induced alopecia is a rare condition that needs to be differentiated from other causes of hair loss; however, further studies are needed to elucidate the exact mechanism by which ants attack the hair.

CONFLICT OF INTEREST

The authors have no conflict of interest to declare.

AUTHOR CONTRIBUTIONS

Dr. Z.G was responsible for management of the patient and patient follow‐up and provided photographs. Dr. V.R.V and Dr. S.Z.R were drafting the manuscript and reviewed the literature. Dr. M.A was responsible for revising the manuscript and also follow‐up of the patient.

ETHICAL APPROVAL

This study was reviewed by the ethics committee of Shahrekord University of Medical Sciences and was approved with the code of IR.SKUMS.1400.075.

Ganjei Z, Reisi‐Vanani V, Razavi SZ, Alizadeh M. Ant‐induced alopecia: A new differential diagnosis for nonscarring alopecia. Clin Case Rep. 2021;9:e04648. 10.1002/ccr3.4648

DATA AVAILABILITY STATEMENT

The authors confirm that the data supporting the findings of this study are available within the article.