- Adult Acne Defined
- The Two Types of Adult Acne
- Causes of Adult Acne
- Comparison of Features in Adult and Adolescent Acne
- What Studies Can Tell Us about Adult Acne
Adult Acne Defined
People often think of acne as a condition that affects teenagers that disappears naturally after adolescence, but different studies have shown that significant percentages of adults experience acne as well. Adult acne is normally defined as acne in persons 25 years of age or older.1
The Two Types of Adult Acne
There are two types of adult acne.1
- Persistent acne begins during adolescence and continues into adulthood
Late-onset acne begins during adulthood, affecting people who did not suffer from acne during adolescence
Causes of Adult Acne
Although the underlying causes of adult acne have not been thoroughly investigated, researchers in a 2006 report published in the American Journal of Clinical Dermatology claim that many of the same biological processes and other factors related to adolescent acne may also play some role in adult acne:
“However, thus far, no clear causes for the clinical difference between adult and adolescent acne have been delineated, although endocrine abnormality, genetic predisposition, antibiotic resistant Propionibacterium acnes, cosmetics, smoking, and emotional stress are regarded as potential risk factors for the development of adult acne.”2
Let’s explain these factors in layman’s terms and look at what each entails.
Endocrine abnormality (hormone imbalance). Acne is generally caused by an imbalance of hormones, which are produced by the endocrine system. Androgens, which are male hormones that are also present in females to a lesser degree, are primarily responsible for triggering acne. The increased production of these hormones contributes to the following events, which work together to cause acne.
- Increased sebum (skin oil) production in the pores
- Skin pores that become clogged by the protein keratin--which is produced by skin cells called keratinocytes--thus trapping sebum
- Increased growth of the bacteria Propionibacterium acnes (P. acnes), which lives in everyone’s skin--regardless of whether she has acne
- Inflammation, which is the characteristic that makes pimples red and swollen2,3
Adolescent acne usually goes away with age--when hormone levels stabilize--but adult acne still occurs in some people for reasons that are not fully understood.4
Genetic predisposition (genes). If a person’s parents suffer from a certain disease, he is more likely to develop that disease. In the case of adult acne, people who have relatives or a family history of adult acne are more likely to deal with it as well. However, studies on twins have revealed that, in addition to genetics, environmental factors can also contribute.5–7
P. acnes grows inside a pore and may contribute to the redness that we see in inflamed pimples.
Some Cosmetics and skincare products contain pore-clogging ingredients. Dermatologists refer to products that tend to clog pores as “comedogenic.”2
Emotional stress. It has not been proven, but some researchers believe that stress affects how the immune system responds to infections, including infections by P. acnes. Stress may also affect how the body regulates hormones, which can trigger acne.2
Smoking. Not everyone in the acne research community agrees that smoking causes acne--some studies support this idea, and some do not. Some researchers have suggested that smoking results in acne by altering the composition of sebum. 8–10
Diet. Although some research has indicated that high-sugar foods can bring about acne in some people, studies on diet and acne are mostly reliant on surveys and lack rigorous testing methods.11
Comparison of Features in Adult and Adolescent Acne
There are some notable differences in how acne strikes adults compared to adolescents. Adult acne tends to affect women more than men, whereas adolescent acne affects boys more than girls. Adults with acne tend to get fewer comedones (clogged pores) than adolescents with acne, but adult acne can produce pimples with more inflammation. Consequently, adult acne leads to scarring more often than adolescent acne.1 Both adult and adolescent acne can affect the face, neck, and torso. Several studies have demonstrated that adult acne is particularly present on areas near the cheeks, chin, and mandible (jaw) in both men and women.1,12–14 Below is a visible comparison of the features often seen in adolescent and adult acne.15
Representative patients showing different observed characteristic of acne according to age of onset: (a) Typical features of adolescent acne: Many comedones on the forehead and a few papules (inflammatory lesions) on the cheeks are observed. (b) Late-onset acne: Papules distributed mainly on the cheeks and chin.
The differences in features of adolescent and adult acne are organized in the table below.1
What Studies Can Tell Us about Adult Acne
Although there is much that researchers don’t understand about adult acne, scientific studies have been able to provide answers to some of the questions that people may have about it. The table below summarizes answers to some of these questions, based on the best research that is currently available. Details about the studies are explained further in this article.
Late-onset acne affects women more than men
In a 2012 study published in the Indian Journal of Dermatology, Venereology and Leprology, there was clear evidence that women are more affected by late-onset acne than men. The study included 280 adults with acne, 230 of which were women, and 50 were men. The participants were over 25 years of age, with the average age being 30.5 years. Late-onset acne was experienced by 26.8% of the participants. This group included mostly women--73 females, compared to only 2 males. The other 73.2% of participants experienced persistent acne--a group that included 160 females and 45 males. The severity of acne was mostly moderate among males and females, and both genders also had similar types of acne.1
The tendency for adult acne to affect women more than men was also shown in a 2011 study in the International Journal of Dermatology, which also looked at how acne affected different age groups. This study included 225 female and 320 male participants with acne. The average age of the female participants was 24.5 years, and the average age of the males was 23.1 years. The results showed that females over the age of 30 were far more likely to have adult acne than males over the age of 30. The table below shows this data, as well as how often acne occurred in the other age groups. Acne was most prevalent in the adolescent age groups, and less prevalent in the adult age groups.13
Hormonal changes can cause acne to affect women in adulthood
Menstrual cycles may cause adult acne to affect women more than men. The cycles cause changes in androgen levels, which are related to premenstrual flares of acne in adolescents as well as adult females.
A 2014 study in the journal Archives of Dermatological Research reported that among 28 female participants with adult acne, 37% also possessed excess amounts of androgens. The diagram below shows how this factor combines with other factors to cause adult acne in women.16
Persistent acne is more common than late-onset acne, and may be more severe
Adults who experience acne are far more likely to have persistent acne, rather than the late-onset variety.
This was shown in a 2012 study published in the journal Acta Dermato-Venereologica. The study included 1399 participants of all ages who had acne, both male and female. Adult acne affected 25.7% of the participants in the study. Of these adults, 83.3% had persistent acne, and the other 16.7% had late-onset acne. The researchers found that adult acne was most prevalent in people during their late 20s, with a decrease in the decades that followed. Other data from the study, noted in the table below, showed the following.1
- Persistent acne cases were slightly more severe than late-onset acne
- Persistent acne resulted in more premenstrual flares than late-onset acne
Women are affected by late-onset acne more than men
The previously mentioned 2012 study from the Indian Journal of Dermatology, Venereology and Leprology also showed that persistent acne was more common than late-onset acne, and late-onset acne affected women more than men.
The cheeks, chin, and jaw areas are most prone to adult acne
While adolescent and adult acne both affect the face, research shows that adult acne is particularly common on the cheeks, chin, and jawline.
In the previously mentioned 2012 study published in the Indian Journal of Dermatology, Venereology and Leprology, researchers recorded where acne occurred among the 280 male and female adult participants, and found that:
- 81% of the participants had acne on the cheeks
- 67% of the participants had acne on the chin
58.3% of the participants had acne on the jaw area
The graph below shows the similarities and differences in how men and women with adult acne experienced acne on the U-zone as well as on the T-zone, which comprises forehead and nose areas.1
Late-onset acne causes fewer comedones, but more inflammation than persistent acne
A 2011 study published in the Journal of the European Academy of Dermatology and Venereology focused on the differences between persistent and late-onset adult acne in women. The study showed that late-onset acne was generally less severe and presented fewer comedones than persistent acne. This study included 89 female participants with adult acne and distinguished them based on the age at which their acne began. Researchers defined late-onset acne as acne occurring after the age of 21. Cases of acne that started before 21 years of age were considered persistent adult acne. The results showed that women with late-onset acne had fewer lesions, but those lesions were more inflamed or swollen. This study also provided more data showing that adult acne is likely to occur on the U-zone, while adolescent acne may be more likely to occur on the T-zone. The researchers also found that the levels of P. acnes and sebum production in the skin were similar in both late-onset and persistent adult acne types.15
The proportion of adults who have acne varies widely
A variety of acne studies conducted on groups of people in different countries reported incidences of adult acne. The following table summarizes the findings, and how they are categorized. There is some variation in how prevalent acne is, depending on gender, age, and ethnicity. Because of these variations, it is difficult to estimate how often adult acne that would be true for all adults occurs. But generally, we estimate that 31.9% of women and 20.5% of men between the ages of 20 and 70 years old are affected by acne, based on these studies.
Study-results on how genders are affected by adult acne:17-21
Study-results on how the frequency of adult acne diminishes with age:18, 22
Study-results on how often adult acne occurs in different ethnicities:23-25
Adult acne is caused by the same factors as adolescent acne, but there are some notable differences in how it presents. Persistent adult acne is far more common than late-onset adult acne. Late-onset adult acne tends to affect women more than men, but adult acne in general is particularly common on the cheeks, chin, and jawline. In these regions, fewer comedones but more inflammation are seen than in adolescent acne.