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Circumscribed scalp hair loss following multiple hair-cutter ant invasion

  • Author(s): Aghaei, Shahin, MD
  • Sodaifi, Manouchehr, MD
  • et al.
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Circumscribed scalp hair loss following multiple hair-cutter ant invasion
Shahin Aghaei MD, and Manouchehr Sodaifi MD
Dermatology Online Journal 10 (2): 14

Shiraz University of Medical Sciences, Shiraz, Iran. shahinaghaei@yahoo.com

Abstract

A 32-year-old woman presented with an abrupt, localized loss of scalp hair that occurred on the previous day. Her nails, skin, and mucosae were normal. On the vertex of the scalp, there was a circular patch of alopecia; the hairs were broken at approximately equal lengths above the skin surface. Several erythematous macules were seen in the affected area, but scale, twisted hair, and exclamation-mark hairs were not present. Further examination revealed the presence of ants on the scalp. This patient is one of several referred to our department presenting with hair loss associated with hair-cutter ant invasion.



Clinical synopsis


Figure 1 Figure 2
A round-shaped, localized, and hairless patch over the vertex (Fig. 1)
A hair tuft with several ants (Fig. 2).

Figure 3 Figure 4
Several live Pheidole ants (Fig. 3).
Near view of a Pheidole ant (Fig. 4).

A 32-year-old woman presented with an abrupt, localized loss of scalp hair that occurred on the previous day. Other than a thyroidectomy scar on anterior neck and a history of post-surgical hypothyroidism and hypoparathyroidism (under treatment with levothyroxine, calcium supplement, and vitamin D3), she was healthy. Her nails, skin, and mucosae were normal.

On the vertex of the scalp, there was a circular patch of alopecia; the hairs were broken at approximately equal lengths above the skin surface (Fig. 1). Several red macules, interpreted as sting points, were present within the area of alopecia, but scale, twisted hair, and exclamation-mark hairs were not present. Further examination revealed the presence of ants on the scalp (Figs. 2-4). The ants appeared to belong to the Pheidole species.


Discussion

The hair-bearing areas of man and animals are hosts to, or may be affected by, many arthropods. Man may be infested with lice on the scalp, pubic hairs, and eyelashes [1]. Sharma and et al. reported a patient who developed generalized scalp hair loss following multiple honey-bee stings [2]. Skin lesions on elk with ticks comprise broken hair and alopecia involving the dorsal portion of the lower neck, often extending in a collar around the neck [3].

Many ant species are equipped with powerful stings and are capable of inflicting painful bites. There are two main groups in the super family of Formicoidea ants, the Myrmecioid complex, including Australian jumper and bull ants, and the Poneroid complex contains species of Solenopsis, the fire ant, and Pheidole [4]. The Pheidole species are dimorphic, brown-red ants (i.e., they have two sizes in a colony) [5]. The smaller size, or minor worker, gathers seeds; the larger, or major worker, uses its oversized head and jaws to break open seeds [1, 6, 8].

The first report of ant-induced hair loss was published by Radmanesh and Mousavipour [7], and the second by Shamsadini [8], both from Iran.

In our patient, the scalp hairs had been broken at approximately equal lengths, just near the scalp. Several red sting points were seen over the area.

Other causes of sudden hair shedding, such as alopecia areata and trichotillomania, were ruled out. The patient did not have exclamation-mark hairs [9], alopecic patch, and nail changes, the hallmarks of alopecia areata. She had no twisted hairs and no psychological problems [10], the hallmarks of trichotillomania.

Pheidole ants are believed to be lipophilic and therefore attracted to relatively greasy scalps [7].

According to our knowledge, our patient is the third documented case of ant-induced alopecia, and this infestation has not been reported from other countries.

Acknowledgment: We are very grateful to the patient who gave us written consent for publication of this information.

References

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2. Sharma AK, Sharma RC, Sharma NL. Diffuse hair loss following multiple honeybee stings. Dermatology. 1997;195(3):305. No abstract available. PubMed

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9. Jackson D, Church RE, Ebling FJ. Alopecia areata hairs: a scanning electron microscope study. Br J Dermatol. 1971 Sep;85(3):242-6. PubMed

10. Muller SA. Trichotillomania: a histopathologic study in sixty-six patients. J Am Acad Dermatol. 1990 Jul;23(1):56-62. PubMed

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