Isolated Unpigmented Trichomegaly of the Groin in 3 Patients

Dear Editor,

We have recently had the chance to observe the abnormal presence of a long isolated white hair in the groin area of a Caucasian healthy 49-year-old male university professor.

The professor visited our office due to an irritant eczema in the groin area after a long run on a humid day and we could observe, by chance, the presence of this abnormal hair being 8-10 cm long (fig. 1), intermingled with normal pubic hair (1-2 cm long). A precise observation of the zone revealed that most pigmented hairs were short and thin and normally curled, but the canities were all relatively longer (4-5 cm) and just 2 of them exceptionally long (6-10 cm).

Fig. 1.

A 12-cm-long white hair was found in a 49-year-old healthy Caucasian male in the groin area (patient 1).

We could not observe any significant difference between the pigmented and unpigmented hairs with a dermatoscope, and the patient refused a biopsy. We decided to further investigate the groin of other middle-aged patients and we were lucky to find 2 other subjects with similar findings (fig. 2, 3).

Fig. 2.

Patient 2 showed a similar finding as patient 1 on the scrotum.

Fig. 3.

Patient 3 showed several long unpigmented hairs mixed with normal ones in the groin area.

The second patient was a 52-year-old male under no oral medication who consulted us about an itchy scrotum. The third patient was a 61-year-old Caucasian male with no relevant past history who came to get rid of some seborrheic keratosis, and his dermatologist took the opportunity to explore his groin area looking for unpigmented trichomegaly. They both had similar clinical findings, i.e. normal curly pigmented hair with few abnormally long white hairs. Both refused biopsy, and dermatoscopy did not show significant findings.

In the literature, there is no evidence on the difference in the growth rate of pigmented and gray hair, and we could not find any article regarding this very peculiar observation. There has always been a discussion among hair scientists about gray hair being thicker or growing faster than pigmented hair, but no conclusive papers ever demonstrated this hypothesis.

In the literature, we could find a recent paper by Bernabó et al. [1] on an isolated long white eyelash but no other similar papers could help us understand our findings. In the paper by Bernabó et al. [1], they did a PubMed search but found no similar reported cases. However, when they searched the Internet, they found several sites showing similar cases, including internet forums, a Facebook site, YouTube video, and a Guiness World Record.

We found nothing similar on the net. Other papers that could help better understand the growth differences between hair and body areas could be those regarding essential trichomegaly of the eyelashes [2]. In those cases, trichomegaly is not always isolated and hair usually keeps its pigment.

The origin of the abnormal growth and decoloration is not clear to us. Hormonal senile changes, a hidden hamartoma, a pilomatricoma, or even a very selective type of benign adnexal tumor could be involved in the pathogenesis of this situation.

We hope that other future cases may shed some light into this very peculiar finding.

Statement of Ethics

This study complies with the guidelines for human studies and animal welfare regulations. I hereby state that the subjects in this letter have given their informed consent. There is no animal experiment in our letter.

Disclosure Statement

I hereby declare to have no conflict of interest regarding the paper.