Adult Acne - Everything You Need to Know

• 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
• Conclusion

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

1. Persistent acne begins during adolescence and continues into adulthood
2. 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:

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.

1. Increased sebum (skin oil) production in the pores
2. Skin pores that become clogged by the protein keratin - which is produced by skin cells called keratinocytes - thus trapping sebum
3. Increased growth of the bacteria Cutibacterium acnes (C. acnes), which lives in everyone's skin - regardless of whether she has acne
4. Inflammation, which is the characteristic that makes pimples red and swollen^2,3

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

C. 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 C. 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

Two large studies have shown that late-onset acne is much more common in women than in men.^1,13

The second large study also looked at how often acne occurred in different age groups, and the results of this comparison are shown in the table below.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 recent study found that about a third of women with adult acne have abnormally high androgen levels.¹⁶ Excessive amounts of androgens at certain points during the menstrual cycle may be one of the factors contributing to adult female acne, as shown in the diagram below.

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. We have evidence of this from a large 2012 study that included nearly 1400 participants. This study found that among people with adult acne, over 80% suffer from persistent acne, and that persistent acne tends to be slightly more severe than late-onset acne. The researchers also concluded that adult acne is most common in people who are in their late 20s, and that acne incidence decreases in the following decades.¹

Another study confirmed the finding that persistent acne is more common than late-onset acne, and again, found that late-onset acne is more likely to strike women than men.¹

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.¹

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 study that looked at women with adult acne found that women suffering from late-onset acne had fewer acne lesions than women with persistent acne. However, the researchers also observed that lesions in late-onset acne were more inflamed or swollen compared to lesions in persistent acne.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

Conclusion

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.