Acne was long considered a skin disease only affecting adolescents. It is now known that many adults also have acne-prone skin and can experience blemishes after the age of 30 or even 40, well after the end of puberty.
The French Dermatology Society (SFD) estimates that 25% of French people are affected. This figure ranges from 41% to 54% for adult women depending on the study. What is the standard profile of an adult with acne, what are the causes of adult acne, and what factors promote the onset of acne?
Overall, women are more affected than men. Acne tends to affect the face in women and the back and neck in men. This difference in the location of pimples explains why acne has a much greater impact on the quality of life and self-image of women.
The influence of hormones is real for many women, who observe acne flare-ups right before their period begins. The production of androgens, which are male hormones involved in acne, peaks during the premenstrual period. However, experts suggest that there are many other responsible factors.
Problems with skin blemishes:
Unlike the skin of an adolescent, the skin of an adult woman is less seborrhoeic, meaning that it produces less sebum. Blemishes are mainly located on the lower face (chin, neck, lower jaws). They tend to be chronic and recurring inflammatory (red spots) and comedonal (blackheads) lesions.
To correct these skin problems, appropriate treatments are necessary; they are not the same as those used for adolescent acne.
Hormones
For some women, the dermatologist will look for signs of excess androgen production that might explain the persistence of pimples and skin blemishes. Such signs can include excessive hair growth, irregular or absent periods, weight gain, and hair loss. Only a blood test can confirm the diagnosis, which is relatively uncommon.
Chronic immune system stimulation
Another hypothesis is the development, in the pilo-sebaceous follicles, of strains with resistance to the Cutibacterium acnes bacterium. This pro-inflammatory bacterium is thought to maintain chronic inflammation, continuously stimulating the immune system. This inflammatory dimension is typical of adult acne in women.
A sebaceous gland problem
Although nothing has been confirmed, some researchers are studying the pilo-sebaceous follicles, in particular the mechanism of sebum secretion, to understand why pimples continue to form in adulthood. Others are focusing on the enzymes involved in producing and breaking down sebum and lipids in the sebaceous glands and skin.
The role of the skin microbiome
We know that the skin is colonised by good and bad bacteria and that healthy skin largely depends on the balance of this skin flora or microbiome. In addition, the Cutibacterium acnes bacterium, involved in particular in inflammatory acne, is thought to have several different strains with varying degrees of acnegenic potential. Thus, a study published in December 2017 analysed bacterial profiles in two groups of adolescents and adult women with acne, over a period of four years. The results showed no difference in the breakdown of Cutibacterium acnes types between the two groups. It therefore seems that immune system, hormonal and environmental aspects are predominant, at least in the current state of knowledge.
