Acne vulgaris is a common skin condition resulting from clogged hair follicles that frequently appears during adolescence. While the onset of acne often coincides with the intense physical development of puberty, having acne does not strictly confirm that a person is still physically growing in height. Both acne and the growth spurt are initiated by the complex hormonal shifts that occur in the body, but they are driven by different hormones and follow separate timelines. The correlation between the two is therefore a matter of overlapping biological events rather than a direct dependency.
The Hormonal Drivers of Acne
The primary catalysts for acne formation are the androgen hormones, such as testosterone and its potent derivative, dihydrotestosterone (DHT). The surge of these sex hormones during puberty stimulates the sebaceous glands, which are oil-producing glands. This stimulation causes the glands to enlarge and significantly increase the production of sebum, an oily, waxy substance that lubricates the skin and hair. When this excess sebum mixes with dead skin cells, it can clog the hair follicles, creating an environment favorable for bacterial growth. The naturally occurring skin bacterium, Cutibacterium acnes, then proliferates within the blocked pore. This colonization triggers an inflammatory response from the immune system, resulting in the visible lesions associated with acne, such as whiteheads, blackheads, and inflamed pimples.
Growth Spurt and Skeletal Maturity
Physical growth, particularly the rapid increase in height known as the growth spurt, is largely controlled by the growth hormone (GH) and Insulin-like Growth Factor 1 (IGF-1). GH is secreted by the pituitary gland and stimulates the liver and other tissues to produce IGF-1. IGF-1 is the main regulator of linear growth, acting locally on the specialized cartilage structures known as growth plates, or epiphyseal plates, located near the ends of long bones. Within the growth plates, IGF-1 promotes the division, proliferation, and enlargement of cartilage cells, which are then replaced by bone through a process called endochondral ossification. This continuous process extends the length of the bones, resulting in increased height. The process of linear growth permanently ends when the rising levels of sex hormones, specifically estrogen in both sexes, cause the growth plates to fuse and harden into solid bone.
Decoupling the Timelines of Acne and Growth
While both the growth spurt and acne are products of the pubertal hormonal surge, their dependence on hormone levels and their timelines differ. The initial rise in androgens is often sufficient to stimulate the sebaceous glands and start acne production relatively early in puberty. This means acne can begin when a person is still in the early phases of their growth spurt. However, the closure of the growth plates, which marks the end of linear growth, requires a sustained, higher level of sex hormones, particularly estrogen. This closure typically happens later in adolescence, often years after acne first appears and after the peak velocity of the growth spurt has passed. It is common to continue experiencing acne well after the growth plates have fused and height gain has stopped. The presence of acne indicates that the sebaceous glands are still sensitive and responsive to circulating hormone levels, not that the skeleton is still lengthening.
Factors Causing Acne in Adults
The persistence of acne beyond the end of physical growth is evidence that it is not solely a marker of immaturity or growth. Many adults, particularly women, continue to experience acne due to hormonal fluctuations unrelated to the growth process, such as those occurring during the menstrual cycle, pregnancy, or perimenopause. Genetics also plays a significant role, predisposing some individuals to overly sensitive sebaceous glands that react to even normal adult hormone levels. External and internal factors can also trigger adult acne by increasing sebum production or inflammation. Psychological or physical stress causes the release of the hormone cortisol, which can stimulate oil production and worsen breakouts. Certain medications, including corticosteroids and some antidepressants, can also contribute to the development of acne in individuals who have already reached full skeletal maturity.