Published online March 1, 2006
PEDIATRICS Vol. 117 No. 3 March 2006, pp. 951-954 (doi:10.1542/peds.2005-1227)
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EXPERIENCE AND REASON

Pubic Hair of Infancy: Endocrinopathy or Enigma?

Todd D. Nebesio, MD and Erica A. Eugster, MD

Department of Pediatrics, Section of Pediatric Endocrinology/Diabetology, James Whitcomb Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, Indiana


   ABSTRACT
TOP
 ABSTRACT
CASE SERIES
 DISCUSSION
 CONCLUSIONS
 REFERENCES
 
Pubic hair of infancy is a rare condition that has not been well-characterized. A retrospective chart review of infants <12 months of age who presented to our pediatric endocrine clinics with isolated pubic hair over the last 5 years was performed. Eleven patients were identified (6 male and 5 female). The average age at diagnosis was 8.3 ± 2.0 months. The majority of patients (73%) had pubic hair in an atypical location. Growth pattern, laboratory evaluation, and bone-age radiographs were unremarkable for all the infants. Of the infants that returned for follow-up, pubic hair resolved by the age of 11.0 ± 1.5 months. From our experience and review of the literature, we suggest that isolated pubic hair of infancy is a benign entity. However, long-term follow-up needs to be done to determine if pubic hair of infancy is an atypical variant of premature adrenarche, which may place these patients at risk for later adult disease.

Key Words: pubic hair • infancy • premature adrenarche • precocious puberty

Abbreviations: 17-OHP, 17-hydroxyprogesterone • DHEA, dehydroepiandrosterone • ß-hCG, ß-human chorionic gonadotropin

Premature adrenarche refers to the development of isolated pubic hair in children before the age of 8 years in girls and 9 years in boys.1 Premature adrenarche appears more frequently in girls2 and most commonly occurs between the ages of 6 and 8 years. In contrast, children who present with isolated pubic hair during the first 12 months of life are thought to be rare. Furthermore, pubic hair of infancy has not been well-described in the literature.3

Here we report our experience with infants presenting with isolated pubic hair. We sought to determine how often a pathologic process was identified and whether there were any consistent clinical or environmental features that might provide a clue as to the etiology of this unusual finding. We also review the medical literature of infants who present with isolated pubic hair. To our knowledge, this study represents the largest case series of children presenting with pubic hair of infancy that has been reported to date.


   CASE SERIES
TOP
 ABSTRACT
 CASE SERIES
DISCUSSION
 CONCLUSIONS
 REFERENCES
 
After institutional review board approval, we identified medical charts of children who presented to our pediatric endocrine clinics from 1999 to 2004 with pubic hair of infancy. Inclusion criteria for the study were infants <12 months of age with no other signs of premature sexual development. Patients with vellus hair were excluded. Eleven eligible infants (6 male and 5 female) were identified. Patient characteristics and clinical course are shown in Table 1. The ethnic background of these children included 5 black (45%), 3 white (27%), 1 Hispanic (9%), and 2 others (18%). The majority of infants were born term (82%). The mean ± SD score of length for age was 0.0 ± 1.1, and the mean ± SD score of weight for age was 0.1 ± 0.9. The weight-for-length ratio was >95th percentile in 1 patient (patient 5). One mother noted development of mild hirsutism during pregnancy; however, this resolved before delivery.


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  		TABLE 1 Clinical Characteristics of Infants Presenting With Isolated Pubic Hair

 
The average age when pubic hair was first noted by a caregiver was 5.3 ± 2.5 months (range: 2–9 months). The average age when infants were seen in our clinic and diagnosed with pubic hair of infancy was 8.3 ± 2.0 months (range: 5.5–11.5 months). Family history was negative for all patients for early pubic hair development in infancy or childhood. There was no history of exposure to exogenous hormones in any of the patients. None of the infants were on soy formula. The majority of patients (64%) were on no medications and had no medical problems. Those infants who had significant medical problems included reactive airway disease, multiple ear infections, hemoglobinopathy (sickle cell disease), and failure to thrive.

No other signs of virilization or secondary sexual development were noted in any of the infants, specifically no penile or clitoral enlargement or growth acceleration. In all of the boys, the pubic hair was located only on the scrotum. An example of isolated pubic hair in one of the patients is shown in Fig 1. In girls, pubic hair was present on the labia majora in 3 infants and confined to the mons in 2 infants. Bone-age radiographs were obtained for the majority (73%) of patients, and all were equal to the chronologic age. A combination of laboratory tests, including obtaining 17-hydroxyprogesterone (17-OHP), testosterone, estradiol, dehydroepiandrosterone (DHEA)-sulfate, DHEA, androstenedione, and ß-human chorionic gonadotropin (ß-hCG) levels, were performed in 91% of the patients. Table 2 summarizes the laboratory evaluation that was performed in each infant at diagnosis. All laboratory tests were normal for age except in 2 patients who had significantly elevated 17-OHP levels of 294 ng/dL (patient 6) and 415 ng/dL (patient 8). Patient 6 also had a mildly elevated DHEA level, and patient 8 had a minimally elevated androstenedione level, which both correspond with the elevated 17-OHP levels. These results were not felt to be significant, because the assays were performed in a general rather than specialty endocrine laboratory, and the rest of the medical evaluation was entirely normal. It is notable that both of the patients with elevated 17-OHP levels were born preterm, because preterm infants often have falsely elevated 17-OHP levels.4


Figure 1
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  		FIGURE 1 Example of an infant boy (patient 6) who presented with isolated pubic hair confined to the scrotum.

 

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  		TABLE 2 Laboratory Studies for Each Infant at the Time of Initial Evaluation and Diagnosis of Isolated Pubic Hair of Infancy

 
Of the 11 patients, 36% returned for follow-up. All infants who returned were seen by the same pediatric endocrinologist at the initial and all subsequent visits. Among these infants, growth velocity was normal for age at 17.9 ± 1.9 cm/year. From the time it had first been noted in the clinic, pubic hair resolved at an average age of 11.0 ± 1.5 months (range: 10–12.5 months) in all cases.


   DISCUSSION
TOP
 ABSTRACT
 CASE SERIES
 DISCUSSION
CONCLUSIONS
 REFERENCES
 
Here we describe 11 infants (6 male and 5 female) who presented to our pediatric endocrine clinics with isolated pubic hair of infancy. We were unable to identify any pathologic process or specific etiology in any of the cases. All of our patients had reassuring growth records, laboratory evaluations, bone-age radiographs, and physical examinations.

Previous reports of isolated pubic hair of infancy3,5–10 are summarized in Table 3. As seen in our patients, these studies indicate that the pubic hair in boys most commonly resolves or decreases over the first few years of life,6,7,9,10 which suggests that it may be caused by a transient, undefined phenomenon. The etiology of isolated pubic hair during infancy remains unknown, although some reports have suggested a heightened cellular response10 or an increased sensitivity8 of hair follicles to androgens. Others have proposed that the minipuberty of infancy in boys may account for pubic hair development corresponding to the early physiologic rise in testosterone.6,9 Although this explanation would seem logical for pubic hair development in boys, this theory does not account for the development of pubic hair in girls, who lack an androgen surge and were represented equally in our study sample. However, a number of reports have noted pubic hair development with or without breast enlargement in young children and infants after exposure to estrogens only.11–15 Therefore, it may be possible that the estrogen surge experienced by girls during the putative minipuberty of infancy16 could account for pubic hair development. Infant hair follicles may be responsive to small amounts of estradiol that are not detected by laboratory assays. Researchers have noted extensive individual variability in infant female hormone concentrations, with many values falling below the threshold of detection for various assays.17 Similar to patient 8, pubic hair regression in young girls has been reported previously,11,12 although these cases occurred after a known exposure to estrogen was removed. Despite this intriguing hypothesis, sex-steroid levels were prepubertal or unmeasurable in all patients at the time of initial evaluation.


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  		TABLE 3 Review of Reports in the Medical Literature of Infants Presenting With Isolated Pubic Hair

 
As first described by Marshall and Tanner, normal pubic hair development in boys begins at the base of the penis18 and in girls along the medial surface of the labia.19 It is interesting to note that 73% of the patients in our series had an atypical location of pubic hair, specifically on the scrotum in boys (100%) and on the mons in girls (40%). The explanation for this finding is unclear. Possible reasons, although not proven, include increased local 5-{alpha}-reductase activity or a different distribution of androgen receptors in infancy.

The differential diagnosis of pubic hair in prepubertal children includes premature adrenarche and pathologic hyperandrogenism. Although considered a variation of normal development, premature adrenarche has now been established as a frequent forerunner of adult diseases1 including polycystic ovarian syndrome,20 hyperinsulinism, dyslipidemia, and early cardiovascular disease.21 If pubic hair of infancy represents an extreme form of premature adrenarche, these patients may be at higher risk for future adult diseases, which would warrant close monitoring and long-term follow-up. Hyperandrogenism in infants may be caused by precocious puberty,22 classic or nonclassic congenital adrenal hyperplasia,4 virilizing tumors,23 or exogenous exposure.11,14,15 However, additional abnormalities including clitoromegaly, increased penile length, advanced bone age, and growth acceleration are invariably present in these pathologic conditions.

One weakness of this study is that it is a retrospective chart review and all patients were referred to the subspecialty clinic. Therefore, the true incidence of early pubic hair development in infants may be even higher. Another flaw of this study is that we have incomplete follow-up. However, it is likely that infants lost to follow-up had a similar clinical course to those who returned to our clinic, because our institution was the only tertiary pediatric referral center in the state at the time that these patients were seen in our clinics.


   CONCLUSIONS
TOP
 ABSTRACT
 CASE SERIES
 DISCUSSION
 CONCLUSIONS
REFERENCES
 
Isolated pubic hair of infancy, although considered abnormal, seems to be a benign entity. Prospective long-term studies are needed to determine if children with a history of pubic hair of infancy develop metabolic derangements later on in life.


   FOOTNOTES
 
Accepted Jun 30, 2005.

Address correspondence to Todd D. Nebesio, MD, Pediatric Endocrinology/Diabetology, Riley Hospital for Children, 702 Barnhill Dr, Room 5960, Indianapolis, IN 46202. E-mail: tdnebesi{at}iupui.edu

The authors have indicated they have no financial relationships relevant to this article to disclose.


   REFERENCES
TOP
 ABSTRACT
 CASE SERIES
 DISCUSSION
 CONCLUSIONS
 REFERENCES
 

  1. Ibanez L, Dimartino-Nardi J, Potau N, Saenger P. Premature adrenarche: normal variant or forerunner of adult disease? Endocr Rev. 2000;21 :671 –696[Abstract/Free Full Text]
  2. Saenger P, Reiter EO. Premature adrenarche: a normal variant of puberty? J Clin Endocrinol Metab. 1992;74 :236 –238[CrossRef][Web of Science][Medline]
  3. Kaplowitz P. Clinical characteristics of 104 children referred for evaluation of precocious puberty. J Clin Endocrinol Metab. 2004;89 :3644 –3650[Abstract/Free Full Text]
  4. Speiser PW, White PC. Congenital adrenal hyperplasia. N Engl J Med. 2003;349 :776 –788[Free Full Text]
  5. Silverman SH, Migeon C, Rosemberg E, Wilkins L. Precocious growth of sexual hair without other secondary sexual development: premature pubarche, a constitutional variation of adolescence. Pediatrics. 1952;10 :426 –432[Abstract/Free Full Text]
  6. Diamond FB, Shulman DI, Root AW. Scrotal hair in infancy. J Pediatr. 1989;114 :999 –1001[CrossRef][Web of Science][Medline]
  7. Rotenstein D, Smith D, Deeb ZL. Scrotal hair in infant with empty sella turcica. J Pediatr. 1990;116 :493 –494[Web of Science][Medline]
  8. Adams DM, Young PC, Copeland KC. Pubic hair in infancy. Am J Dis Child. 1992;146 :149 –151[Abstract/Free Full Text]
  9. Slyper AH, Esterly NB. Nonprogressive scrotal hair growth in two infants. Pediatr Dermatol. 1993;10 :34 –35[Web of Science][Medline]
  10. Francis JS, Ruvalcaba RH. Scrotal hair growth in infancy [commentary]. Pediatr Dermatol. 1993;10 :389 –390[Web of Science][Medline]
  11. Tiwary CM. Premature sexual development in children following the use of estrogen- or placenta-containing hair products. Clin Pediatr (Phila). 1998;37 :733 –740[Abstract/Free Full Text]
  12. Weber WW, Grosman M, Thom JV, Sax J, Chan JJ, Duffy MP. Drug contamination with diethylstilbestrol. N Engl J Med. 1963;268 :411 –415[Web of Science][Medline]
  13. Hertz R. Accidental ingestion of estrogens by children. Pediatrics. 1958;21 :203 –206[Abstract/Free Full Text]
  14. Zimmerman PA, Francis GL, Poth M. Hormone-containing cosmetics may cause signs of early sexual development. Mil Med. 1995;160 :628 –630[Web of Science][Medline]
  15. Beas F, Vargas L, Spada RP, Merchak N. Pseudoprecocious puberty in infants caused by a dermal ointment containing estrogens. J Pediatr. 1969;75 :127 –130[CrossRef][Web of Science][Medline]
  16. Chellakooty M, Schmidt IM, Haavisto AM, et al. Inhibin A, inhibin B, follicle- stimulating hormone, luteinizing hormone, estradiol, and sex hormone-binding globulin levels in 473 healthy infant girls. J Clin Endocrinol Metab. 2003;88 :3515 –3520[Abstract/Free Full Text]
  17. Lee MM. Reproductive hormones in infant girls: a harbinger of adult reproductive function? J Clin Endocrinol Metab. 2003;88 :3513 –3514[Free Full Text]
  18. Marshall WA, Tanner JM. Variations in the pattern of pubertal changes in boys. Arch Dis Child. 1970;45 :13 –23[Abstract/Free Full Text]
  19. Marshall WA, Tanner JM. Variations in pattern of pubertal changes in girls. Arch Dis Child. 1969;44 :291 –303[Free Full Text]
  20. Ibanez L, Potau N, Virdis R, et al. Postpubertal outcome in girls diagnosed of premature pubarche during childhood: increased frequency of functional ovarian hyperandrogenism. J Clin Endocrinol Metab. 1993;76 :1599 –1603[Abstract]
  21. Ibanez L, Potau N, Chacon P, Pascual C, Carrascosa A. Hyperinsulinaemia, dyslipaemia and cardiovascular risk in girls with a history of premature pubarche. Diabetologia. 1998;41 :1057 –1063[CrossRef][Web of Science][Medline]
  22. Lee PA. Central precocious puberty. An overview of diagnosis, treatment, and outcome. Endocrinol Metab Clin North Am. 1999;28 :901 –918, xi[CrossRef][Web of Science][Medline]
  23. Wolthers OD, Cameron FJ, Scheimberg I, et al. Androgen secreting adrenocortical tumours. Arch Dis Child. 1999;80 :46 –50[Abstract/Free Full Text]
  24. Lashansky G, Saenger P, Fishman K, et al. Normative data for adrenal steroidogenesis in a healthy pediatric population: age- and sex-related changes after adrenocorticotropin stimulation. J Clin Endocrinol Metab. 1991;73 :674 –686[Abstract/Free Full Text]
PEDIATRICS (ISSN 1098-4275). ©2006 by the American Academy of Pediatrics

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