Key Clinical Message:
Ant-induced alopecia is a rare cause of acute, localized hair loss.
Considering the diagnosis of ant induced alopecia may eliminate
unnecessary treatments.
Introduction :
Localized hair loss may include various causes. Alopecia areata,
trichotillomania, and tinea capitis are some diseases that can be the
causes of localized hair loss. We can differentiate them by using
clinical and histological examinations. Ant induced hair loss is one of
the uncommon causes of sudden and localized hair loss. Pheidole is the
second largest group of ants that can be found in most parts of the
world. They are reddish-brown with a large head plus strong jaws causing
hair loss (1). We suggest considering the diagnosis of ant induced
alopecia in order to diagnose the differential localized hair loss.
Case :
An otherwise healthy 34-year-old man presented to the dermatology clinic
with the complaint of sudden hair loss since yesterday. The patient
described that he has noticed shed hairs and some ants on his pillow
after he woke up. He had no pruritus or burning sensation. On
examination, an alopecic patch measuring about 4 in 3 centimeters was
observed on the vertex zone which had approximately equal short hairs,
without erythema, scaling and exclamation mark hairs (figure 1). The
patient brought several killed ants with himself. Microscopic evaluation
of ant showed reddish-brown ant with strong jaws that seemed to belong
to the pheidole species (figure 2). Ant-induced alopecia was diagnosed
and we just assured him.
Discussion :
The first reported case of ant induced hair loss was in 1999 from Iran.
Until now, several cases have been reported from Iran and other
countries. The cause of this disease is ants belong to Pheidole species,
mainly Pheidole Pallidula (barber ant) (2). Pheidole species are the
second group of ants which can be found abundantly in many parts of the
world, but they are more expansive in tropical areas. One caste of them
is the worker which is dimorphic and has two classifications: Major and
minor groups. The major group is bigger than the minor one, and their
size is about 6 millimeters (mm) and 4 mm respectively. The soldier ants
(major group) have two pairs of denticles also a middle bump on the
front of their big heads (3). They are responsible for storing food and
protecting the nest (4). In tropical areas, ants often find food at
night, while in the cooler areas they do it at both daytime and night
(1). It is still ambiguous whether the hair loss is related to the ants’
mechanical motility or they have also chemical secretions that can play
a role in this process (1, 5). It manifests as the area of hair loss in
linear or patchy form, without erythema, pruritus, scaling, and
inflammation (2). However, erythema (6, 7) and pruritus probably exist
in some cases (1, 6). Localized and sudden hair loss can have different
reasons, including alopecia areata, trichotillomania, tinea capitis, and
lupus that suggested to be excluded before ant induced alopecia is
diagnosed. To help the diagnosis, we should consider some evidence such
as the ants which exist around the sleeping site, sudden shed hairs with
equal length, and the absence of any signs of inflammation (1). Acute
alopecia areata usually manifests as the following statements: sudden
symptomless one or multifocal patches of hair loss with positive hair
pull test along with cadaverized and exclamation mark hairs and lack of
inflammation signs (8). Tinea capitis is more common in children and
rarely happens in adults. Clinical manifestation varies from scaling
without inflammation to kerion, abscess of subcutaneous tissue with
alopecia, based on the causative organism (9). Trichotillomania is
characterized by a patch of hair loss with different sizes of hair.
Also, hair loss following honey bee stings and tick bites have been
reported, however; in tick bites, inflammatory reactions to bites cause
hair loss and hair growth occurs after subsiding the inflammation(2).
Conclusion :
We can recognize this kind of alopecia by examining and questioning. It
does not need any treatment because hairs will regrow without any
intervention. We find out that ant induced alopecia can simulate the
other causes of localized alopecia also must be aware of this factor as
a cause of alopecia, especially in tropical and subtropical areas.