Pubarche
Pubarche (pyü-bär-kē) refers to the first appearance of pubic hair at puberty and also it marks the beginning of puberty. It is one of the physical changes of puberty and can occur independently of complete puberty. The early stage of sexual maturation, also known as adrenarche, is marked by characteristics including the development of pubic hair, axillary hair, adult apocrine body odor, acne, and increase oiliness of hair and skin. The Encyclopedia of Child and Adolescent Health corresponds SMR2 (Sexual Maturity Rating) with pubarche, defining it as the development of pubic hair that occurs at a mean age of 11.6 years in females (range 9.3–13.9 years) and 12.6 years in males (range 10.7–14.5 years). It further describes that pubarche's physical manifestation is vellus hair over the labia or the base of the penis. See Table 1. for the entirety of the sexual maturity rating description.
A study researched whether thelarche pathway, beginning puberty with breast development alone, or the pubarche pathway, beginning puberty with pubic hair development alone, represents the true pubertal development. The study is an observational, longitudinal cohort study. The study cohort is limited to a group of black and white girls who were seen annually for ten years. It is concluded in the research that pubarche may represent true pubertal maturation.
Assessment
The Tanner scale remains the gold standard for determining pubarche. In clinical settings, this scale is primarily used by physicians, nurses, or other trained healthcare providers as part of a physical examination to assess the stage of puberty in children and adolescents, though in some cases the stage of puberty can be self-assessed[1].
| Tanner Stage | Description of Pubic Hair Development |
|---|---|
| SMR 1 | Prepubertal - No pubic hair |
| SMR 2 | Pubarche - Sparse, fine, straight, downy hair over labia or penis |
| SMR 3 | Appearance of terminal hair - Adult quality, confined to the pubis |
| SMR 4 | Terminal hair fills the pubic region, not beyond inguinal crease |
| SMR 5 | Terminal hair extends onto medial thighs, achieving full adult distribution |
| SMR 6 | Terminal hair extends up the linea alba toward the umbilicus (only in males) |
Average age
The average beginning of pubarche varies due to many factors, including environmental exposures, nourishment, weight, race and ethnicity, and geographic location. First (and often transient) pubic hair resulting from adrenarche may appear between ages 10–12 at the beginning of puberty.
Chemical toxins in the environment are one of many factors influencing adolescent development. In the early 1970s, more than 4000 people were accidentally exposed to polybrominated biphenyls (PBBs).[2] A study was conducted in the child-bearing women exposed to the toxin, with their baby girls reaching menarche by the age of 11.6 years, compared to girls who had low exposure reaching menarche by the age of 12.2-12.6 years.[2] In every day life, people are exposed to a various number of pesticides, with a large amount found to be distruptive to the endocrine system. Although dichlorodiphenyltrichloroethane (DDT) and the metabolite dichlorodiphenyl dichloroethane (DDE) were banned in the United States in the 1970s, countries around the world are still using these pesticides. Studies found that adolescents reached early menarche or thelarche when exposed to DDT and DDE.[2][3] It was determined that women with high exposure reached menarche earlier than women who had low exposure. There were also studies that refuted findings mentioned above, showing that DDT exposure had no correlation with early menarche. Serum DDE levels were studied in females in urban areas as well as places in New York, and cities in Canada, including findings in animals with serum DDE levels exceeding the upper limit determined by the FDA.[2][4] In New York specifically, there was no link between DDE levels and breast development in 9-year-old girls.[5]
Nutrition is vital in adolescent development. Failure to meeting average nutritional needs, such as calcium and vitamin D for bone growth[6], may result in growth stunt. Over-nourishment and/or living a sedentary lifestyle can lead to obesity which can also affect adolescent pubarche. [6]
Delayed Pubarche
Delayed pubarche can be caused by numerous aspects. This can include insufficient hormones, medical or genetic conditions (i.e., Turner syndrome, hypogonadotropic hypogonadism), and chemicals that interfere with the hormones in the body. In young males, genetic differences that impacts the function of enzymes can affect how steroids are eliminated in urine. This can influence the development of pubic hair and can impact the physical appearance from person to person.[7] In young females, the development of breasts and pubic hair can occur at different times. Some may experience breast development before the start of pubic hair growth, and vice versa. Therefore, in order to determine if delayed pubarche is a health issue or not, looking for the signs of puberty happening and the specific timing of it is important to note. The determination of the underlying cause of delayed pubarche can be done so with specific tests of antibodies, karyotype, and hormone levels (i.e, cortisol, thyroid stimulating hormone).[7][8]
Adrenal Insufficiency
Adrenal insufficiency is a life-threatening medical condition in which the adrenal cortex is damaged. This leads to not enough hormones being produced, which include glucocorticoids and mineralcorticoids. These types of hormones are crucial for the regulation of many functions in the body and with not enough levels of these hormones that are produced by the adrenal glands, it can lead to primary adrenal insufficiency.[9] Delayed pubarche can be expected in young males and females with this medical condition due to the lack of hormones that aid for pubic hair growth. Therefore, if signs and symptoms of adrenal insufficiency are present such as fatigue, weakness, abdominal pain, or any history an autoimmune disease, adrenal insufficiency should be taken into consideration as an underlying cause for delayed pubarche.[7][9]
Hypogonadotropic Hypogonadism
Another cause of delayed puberty in both males and females is hypogonadotropic hypogonadism[10], which is a condition in which the male and female genitalia produce little to none of sex hormones. This is a temporary condition in adolescents, usually caused by various stresses, including disease states such as persistent asthma, ulcerative colitis, and sickle cell anemia.[10] Specifically in males, this condition will result in low testosterone levels. Low levels of testosterone can cause levels of other hormones to rise, such as the luteinizing hormone (LH), the follicle-stimulating hormone (FSH), and the gonadotropin-releasing hormone (GnRH).[11] Hypogonadotropic hypogonadism is more prevalent in females, which usually develops under conditions like anorexia nervosa or if the female participates in an adbundant amount of exercise. With these situations decreasing body fat, both estrogen production and secretion will also decrease resulting in delayed puberty, and with it, delayed pubarche. Other health conditions that can cause hypogonadotropic hypogonadism include ovarian failure and autoimmune diseases of the ovaries.[11] Regardless of whether hypogonadotropic hypogonadism is acquired or congenital in males and females, it is always important for providers to conduct detailed familiy and social histories.
Treatment
In males diagnosed with constitutional delay in puberty and growth (CDPG), a short-course of testosterone in low doses is used to initiate puberty. In females diagnosed with CDPG, a short-course of estrogen in low doses is used to initiate puberty.[11] Testosterone is available via oral route or intramuscular injection (IM), with IM being the preferred method of administration because oral testosterone has been shown to have liver toxicity side effects. Estrogen is available via oral route and IM, however oral estrogen is the preferred method of administration.[11] Upon initiation of treatment and thereafter, the adolescent must be monitored for pubertal development, which includes breast development in females and enlargement of the testicles in males.[11] A provider can make a clinical judgement to stop treatment and monitor development while an adolescent is off therapy.
See also
References
- ^ Campisi, Susan C; Marchand, Josée D; Siddiqui, Fahad Javaid; Islam, Muhammad; Bhutta, Zulfiqar A; Palmert, Mark R (2020-08-01). "Can we rely on adolescents to self-assess puberty stage? A systematic review and meta-analysis". The Journal of Clinical Endocrinology & Metabolism. 105 (8): 2846–2856. doi:10.1210/clinem/dgaa135. ISSN 0021-972X.
- ^ a b c d Fisher, Marisa M.; Eugster, Erica A. (2014). "What is in our environment that effects puberty?". Reproductive toxicology (Elmsford, N.Y.). 44: 7–14. doi:10.1016/j.reprotox.2013.03.012. ISSN 0890-6238. PMC 4096833. PMID 23602892.
- ^ Deng, F.; Tao, F.-b.; Liu, D.-y.; Xu, Y.-y.; Hao, J.-h.; Sun, Y.; Su, P.-y. (2012). "Effects of growth environments and two environmental endocrine disruptors on children with idiopathic precocious puberty". European Journal of Endocrinology. 166 (5): 803–809. doi:10.1530/EJE-11-0876. ISSN 0804-4643.
- ^ Denham, Melinda; Schell, Lawrence M.; Deane, Glenn; Gallo, Mia V.; Ravenscroft, Julia; DeCaprio, Anthony P.; and the Akwesasne Task Force on the Environment (2005). "Relationship of Lead, Mercury, Mirex, Dichlorodiphenyldichloroethylene, Hexachlorobenzene, and Polychlorinated Biphenyls to Timing of Menarche Among Akwesasne Mohawk Girls". Pediatrics. 115 (2): e127–e134. doi:10.1542/peds.2004-1161. ISSN 0031-4005.
- ^ Wolff, Mary S.; Britton, Julie A.; Boguski, Lisa; Hochman, Sarah; Maloney, Nell; Serra, Nicole; Liu, Zhisong; Berkowitz, Gertrud; Larson, Signe; Forman, Joel (2008). "Environmental exposures and puberty in inner-city girls". Environmental Research. 107 (3): 393–400. doi:10.1016/j.envres.2008.03.006.
- ^ a b Das, Jai K.; Salam, Rehana A.; Thornburg, Kent L.; Prentice, Andrew M.; Campisi, Susan; Lassi, Zohra S.; Koletzko, Berthold; Bhutta, Zulfiqar A. (2017). "Nutrition in adolescents: physiology, metabolism, and nutritional needs: Adolescents: physiology, metabolism, and nutrition". Annals of the New York Academy of Sciences. 1393 (1): 21–33. doi:10.1111/nyas.13330.
- ^ a b c Baldo, Francesco; Barbi, Egidio; Tornese, Gianluca (2021). "Delayed pubarche". Italian Journal of Pediatrics. 47 (1): 180. doi:10.1186/s13052-021-01134-0. ISSN 1824-7288. PMC 8422600. PMID 34488834.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Gottlieb, B.; Pinsky, L.; Beitel, L. K.; Trifiro, M. (1999). "Androgen insensitivity". American Journal of Medical Genetics. 89 (4): 210–217. doi:10.1002/(sici)1096-8628(19991229)89:4<210::aid-ajmg5>3.0.co;2-p. ISSN 0148-7299. PMID 10727996.
- ^ a b Huecker, Martin R.; Bhutta, Beenish S.; Dominique, Elvita (2023), "Adrenal Insufficiency", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 28722862, retrieved 2023-07-27
- ^ a b Tang, Christine; Zafar Gondal, Anoosh; Damian, Middey (2023), "Delayed Puberty", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 31335042, retrieved 2023-07-26
- ^ a b c d e Tang, Christine; Zafar Gondal, Anoosh; Damian, Middey (2023), "Delayed Puberty", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 31335042, retrieved 2023-07-26
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