Pediatric Dermatology Vol. 13 No. 2 143-145, 1996

Unilateral Localized Failure of Beard Growth Maria Niiiiez, M.D., Enrique S. Miralles, M.D., Josk M. Arrazola, M.D., and

Antonio Ledo, M.D.

Servicio de Dermatologia, Hospital Rambn y Cajal, Universidad de Alacaki, Madrid, Spain

Abstract: Hair may be classified by type as vellus or terminal. The transformation of vellus follicles into terminal follicles Is induced by an- drogens in androgen-dependent areas by promoting the genetic program existing within Individual follicles. Patients with normal androgen plasma levels and absent hair growth in certain areas under androgenic control have been described. One explanation of this condition may be abnormal target tissue sensitivity. We report a 17-year-old man whose only com- plaint was inability to grow a beard on the left side of his face.

The growth of hair in certain areas of the body is recognized to be under androgenic control. There is, however, a proportion of patients with either ex- cessive or absent hair growth in those areas, in whom testosterone values are within the normal range appropriate to their sex. It is postulated that such patients have an abnormal target tissue sensi- tivity to normal levels of androgen. We present a young man whose sole complaint was inability to grow a beard on the left side of his face, the area being covered only with tine vellus hair. In all other aspects he was normal, with androgen levels in the normal male range.

CASE REPORT

A healthy 17-year-old man came to our department . because he never developed terminal hair on the left side of his beard area. He went through puberty at age 13 years and developed terminal hair growth on the right side of his face. He had no history of in- flammation, trauma, or acne on either side of his

Address correspondence to Marla Nddez, M.D.. Servicio de hmatologla, Hospital Ram611 y Cajal, Ctera Colmenar Viejo b9,IOO. 28034 Madrid, Spain.

face. Family history disclosed no similar skin le- sions, alopecia areata, or atopy. In all other re- spects he was normal, with normal axillary and pu- bic hair, normal genitalia, and urinary and plasma androgen levels in the normal range.

On clinical examination, vellus hair was present in the beard area of his left cheek, neck, and chin, and reached just to the midline of the face (Fig. I). His sideburn on the beardless side grew to two- thirds the length of the ear. No exclamation mark hair or readily extracted hairs were observed on the left side of the face. In this area, the rest of the physical examination, including neurologic studies, was normal. Terminal hair growth on all the mus- tache area and on the right side of the beard was normal (Fig. 2).

Routine chemistry, blood cell count, and quanti- fication of immunoglobulins and complement were normal. No endocrine disorder was found. Au- toantibodies to the thyroid, gastric parietal cells, smooth and skeletal muscles, and antinuclear, anti- DNA, and antimitochondrial antibodies were ab- sent.

A skin biopsy was performed on the left (af- fected) and right (nonaffected) sides of the face. The left side only had vellus hairlike follicles (Fig. 3), but on the right side, terminal hair follicles were seen (Fig. 4). The epidermis and dermis were

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Figure 1. Velluslike hair on the left side of the beard area. area.

Figure 2. Terminal hair on the right side of the beard

Figure 3. Histopathology of a velluslike hair from the left side of the face.

Figure 4. Histopathology of a terminal hair from the right side of the face.

N6iiez et al: Unilateral Absent Beard Growth 145

normal without inflammatory infiltrate. Micro- scopic examination of the hair shaft showed no structural defect.

Daily shaving of the right side was recommended to diminish aesthetic problems. At 1.5-year follow- up, no terminal hair growth was seen on the left side.

DISCUSSION

Failure of terminal hair growth, usually on the scalp, is a feature of many hereditary syndromes. The most common forms are nevoid. Single patches of congenital hypotrichosis may occasionally ap- pear in other body sites, but are inconspicuous (1). Sexual hair, found in the upper pubic triangle, along the midline of the abdomen, on the pinna of the ears, in the nares, and in the beard and mustache is stimulated by high male levels of androgens (2-4). In areas of sexual hair, androgens gradually trans- form vellus follicles into terminal follicles (5). This androgen-induced transformation involves changes in the activity of follicular epithelial cells, melano- cytes, and dermal papilla cells (2,6). However, it seems that androgens are able to promote only the genetic program that exists within individual folli- cles (7,8). In our patient the linear or dermatomic distribution suggests a genetic failure, present only in cells derived from the same lineage, showing, therefore, mosaicism.

To the best of our knowledge, this is the first case

described with these characteristic features. We propose the term segmental functional follicular failure of the beard for this defect because of its clinical and histopathologic characteristics.

REFERENCES

1. Barth JH. Circumscribed alopecia of infancy. In: Rook AJ, Dawber RPR, eds. Diseases of hair and scalp. Oxford: Blackwell, 1991: 167-199.

2. Randall VA, Thornton MJ, Hamada K, Messenger AG. Mechanism of androgen action in cultured der- mal papilla cells derived from human hair follicles with varying responses to androgens in vivo. J Invest Dermatol 1992;98:86S-91 S.

3. Randall VA, Thornton MJ, Messenger AG. Cultured dermal papilla cells from androgen-dependent human hair follicles (e.g., beard) contain more androgen re- ceptors than those from non-balding areas of scalp. J Endocrinol 1992; 133: 14 1-147.

4. Garn SM. Types and distribution of the hair in man. Ann NY Acad Sci 1951;53:498-507.

5. Schweikert HU, Wilson JD. Regulation of human hair growth by steroid hormones. I. Testosterone me- tabolism in isolated hairs. J Clin Endocrinol Metab 1974;38:811-819.

6. Thornton MJ, Messenger AG, Elliott K, Randall VA. Effect of androgens on the growth of cultured human dermal papilla cells derived from beard and scalp hair follicles. J Invest Dermatol 1991;97:345-348.

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