What Is The Causes of Acne
All acne is a disorder of the pilosebaceous unit, which is made up of a hair follicle, sebaceous gland, and a hair. These units are found everywhere on the body except on the palms, soles, top of the feet, and the lower lip. The number of pilosebaceous units is greatest on the face, upper neck, and chest. Sebaceous glands produce a substance called sebum, which is responsible for keeping the skin and hair moisturized. During adolescence sebaceous glands enlarge and produce more sebum under the influence of hormones, also called androgens. After about age 20, sebum production begins to decrease.
The root causes of why some people get acne and some do not are not fully known. It is known to be partly hereditary. Several factors are known to be linked to acne:
- Family/Genetic history. The tendency to develop acne runs in families. For example, school-age boys with acne often have other members in their family with acne as well. A family history of acne is associated with an earlier occurrence of acne and an increased number of retentional acne lesions.
- Hormonal activity, such as menstrual cycles and puberty. During puberty, an increase in male sex hormones called androgens cause the follicular glands to get larger and make more sebum.
- Inflammation, skin irritation or scratching of any sort will activate inflammation. Anti-inflammatories are known to improve acne.
- Stress, through increased output of hormones from the adrenal (stress) glands. While the connection between acne and stress has been debated, scientific research indicates that “increased acne severity” is “significantly associated with increased stress levels.” The National Institutes of Health (USA) list stress as a factor that “can cause an acne flare.” A study of adolescents in Singapore “observed a statistically significant positive correlation […] between stress levels and severity of acne.”
- Hyperactive sebaceous glands, secondary to the three hormone sources above.
- Accumulation of dead skin cells that block or cover pores.
- Bacteria in the pores. Propionibacterium acnes (P. acnes) is the anaerobic bacterium that causes acne. In-vitro resistance of P. acnes to commonly used antibiotics has been increasing.
- Use of anabolic steroids.
- Any medication containing lithium, barbiturates or androgens.
- Exposure to certain chemical compounds. Chloracne is particularly linked to toxic exposure to dioxins, namely Chlorinated dioxins.
- Exposure to halogens. Halogen acne is linked to exposure to halogens (e.g. iodides, chlorides, bromides, fluorides).
- Chronic use of amphetamines or other similar drugs.
Several hormones have been linked to acne: the androgens testosterone, dihydrotestosterone (DHT) and dehydroepiandrosterone sulfate (DHEAS), as well as insulin-like growth factor 1 (IGF-I). In addition, acne-prone skin has been shown to be insulin resistant.
Development of acne vulgaris in later years is uncommon, although this is the age group for Rosacea which may have similar appearances. True acne vulgaris in adult women may be a feature of an underlying condition such as pregnancy and disorders such as polycystic ovary syndrome or the rare Cushing’s syndrome. Menopause-associated acne occurs as production of the natural anti – acne ovarian hormone estradiol fails at menopause. The lack of estradiol also causes thinning hair, hot flashes, thin skin, wrinkles, vaginal dryness, and predisposes to osteopenia and osteoporosis as well as triggering acne (known as acne climacterica in this situation).
The Triggers of Acne
Cases of teenage acne are thought to be triggered by increased levels of a hormone called testosterone that occurs during puberty. The hormone plays an important role in stimulating the growth and the development of the penis and testicles in boys, and maintaining muscle and bone strength in girls.
The sebaceous glands are particularly sensitive to hormones, so it is thought that the increased testosterone causes the glands to produce much more sebum than the skin actually needs.
In cases of adult acne, over 80% of cases occur in women. It is thought that many cases of adult acne are a result of the changes in hormone levels that many women will experience at certain points during their life. Possible triggers for adult acne include:
- Periods: some women experience a flare-up of acne just before their period is due.
- Pregnancy: many women experience symptoms of acne during pregnancy, usually during the first trimester (first three months).
- Polycystic ovary syndrome: this poorly understood, but common condition can cause acne, weight gain and the formation of small cysts inside the ovary.
- Side effects of medication: in some people, certain types of medication can cause acne, e.g. steroid medication and lithium (which is often used to treat depression and bipolar disorder).