3 - Hormonal causes of acne


Understanding how hormones work is understanding how acne works in women.

Female acne is a type of inflammatory acne that mainly affects the lower part of the face.

This acne is very often resistant to antibiotic treatments, hormonal treatments and isotretinoin.

It is therefore necessary to carry out an investigation, a hormonal exploration in all these forms to discover the cause.

But before explaining the cause, let's discover together how the female cycle and its hormonal regulation work.

1. Pituitary hormonal control

The hypothalamus, located at the base of the brain, secretes a hormone, GnRH, in a pulsatile rhythm.

This neurohormone directly stimulates the pituitary gland, located just below the hypothalamus.

The hypothalamus allows the interconnection between the nervous system and the hormonal system.

The hypothalamus is itself dependent on the female cerebral cortex and the psyche.

Any major event, emotional shock or psychological disturbance can affect a woman's cycle, delaying or blocking ovulation.

The woman notices this by a change in the length of her cycle.

The pituitary gland secretes two hormones, FSH (follicle stimulating hormone) and LH (luteinizing hormone), also called gonadostimulin, in a cyclical rhythm.

2. Role of hormones

  • Role of FSH: During the first part of the cycle, FSH stimulates the maturation of the ovarian follicles and the secretion of estrogens by these follicles.
  • Role of LH: It acts mainly during a "peak" of secretion, in the middle of the cycle, triggering ovulation. A single mature follicle in the ovary releases its egg into the fallopian tube. The remaining follicle becomes the corpus luteum. LH then stimulates the secretion of estrogen and progesterone from this corpus luteum.

FSH and LH need each other to function.

3. Action of ovarian hormones on the reproductive system

  • Estrogen: helps trigger ovulation, stimulates endometrial proliferation, stimulates the secretion of liquid cervical mucus permeable to spermatozoa, stimulates vaginal secretions.
  • Progesterone: controls the growth of the endometrium to make it suitable for implantation, limits uterine contractions, stimulates the development of mammary glands, stimulates the secretion of thick cervical mucus.

Estrogen and progesterone combine their actions throughout the cycle to cause ovulation, fertilization and eventual implantation of the fertilized egg. These two hormones work in perfect harmony.

4. The development of the female cycle

  • Estrogens: during the female cycle, there are two peaks: the 1st peak responds to the secretion of estrogens by the follicles, i.e. the follicle grows before ovulation. During the 2nd peak, the corpus luteum secretes estrogens. And if fertilization occurs, there will not be a low concentration of estrogen at the end of the cycle.
  • Progesterone: Also secreted by the corpus luteum. Evolves in a single peak during the luteal phase. If fertilization occurs, the fertilization rate is high because the corpus luteum is holding out.
  • Menstruation usually begins 14 days after ovulation, but the cycle can vary from woman to woman. In the absence of hormonal contraception, a woman can get information about the time of her cycle by taking her temperature and observing her cervical mucus.

5. Synthesis of androgens

The origin of androgens in women is, on the one hand, their synthesis by the ovaries (25%) and the adrenals (25%) and, on the other hand, a peripheral conversion of inactive precursors in the liver and target tissues, such as adipose tissue and skin (50%).

The synthesis of androgens by the ovaries is driven by LH. This synthesis is regulated by the effect of estrogens but also by the effect of insulin which can increase the functioning of LH in a situation of hyperinsulinemia.

This synthesis of ovarian androgens leads to the synthesis of testosterone and its precursors: delta-4-androstenedione (Δ4) and dehydroepiandrosterone (DHEA) which are also converted into testosterone (in the ovaries, adrenal glands or target tissues) to be active.

These molecules are also produced by the adrenal glands, only DHEAS (dehydroepiandrosterone sulfate) is exclusively of adrenal origin.

6. The role of androgens

Androgens play a predominant role in the maturation of ovarian follicles.

As they are precursors to estrogen, they balance the estrogen levels necessary for proper follicular development.

Thus, they regulate the female libido and therefore influence sexual desire.

Androgens are also responsible for the development of female hair on the pubic and underarm areas and interfere with the control of sebum production.

They also react in the central nervous system, muscles and bones, as there are androgen receptors in these tissues. They are involved in the maintenance of bone quality and the development of muscle mass.

7. Androgen production and sebum

As previously discussed, the sebaceous gland is equipped with enzymes capable of locally producing androgens from dehydroepiandrosterone sulfate (DEHS).

There are androgen receptors in the basal layer of the sebaceous glands.

It is likely that an excess of circulating androgens, an increase in their number or in receptor responsiveness, are actively involved in the proliferation of inflammatory acne in the sebaceous gland, even if patients have normal testosterone levels.

CONCLUSION

In this exploration of the cause, there are two important terms not to be confused: hyperandrogenism and hyperandrogenemia.

Explication :

  • Acne can be a sign of hypersensitivity to androgens through the skin receptors as we saw in section "2 - Pathophysiology of acne", this is what we call hyperandrogenism.
  • Or acne can be observed in the presence of hyperandrogenemia, the most common cause of which is polycystic ovary syndrome with high levels of androgens.

In this exploration of the hormonal cause, it is necessary to detect the cutaneous signs which must make resemble hyperandrogenism or hyperandrogenemia:

  • severe nodular-cystic acne
  • excess hair or hirsutism
  • female pattern alopecia

Hyperandrogenism is not a necessary condition for hyperandrogenemia, but the higher the circulating levels of androgens, the greater the manifestations of hypersensitivity.

Thus, in women, there are several types of hormonal profiles in acne:

In all this confusion, we now know that the origin of androgens in women comes, on the one hand, from their synthesis by the ovaries (25%) and the adrenals (25%) and, on the other hand, from a peripheral conversion linked to a hyperreceptivity of the sebaceous gland to androgens (50%).

In the case of hyperandrogenism, the synthesis of androgens by the ovaries is driven by LH (luteinizing hormone).

This synthesis is regulated by the effect of estrogens, but also by the effect of insulin, which can increase the functioning of LH in a situation of hyperinsulinemia.

This synthesis of ovarian androgens leads to the synthesis of testosterone and its precursors.

It is also important to note that:

Estrogen is a female steroid sex hormone and acts on sebocytes via estrogen receptor α (ER-α).

Estrogen comes from the transformation of testosterone and its derivatives by aromatase.

They cause an inhibitory effect on excessive sebaceous gland activity in vivo.

In addition, a decrease in estrogen production leads to an aggravation of acne.

They are said to have a protective role against acne, reducing the action and production of androgens and regulating the genes involved in the growth of sebaceous glands or the production of lipids.

This is why many hormonal acne phenomena often occur after stopping the pill and hormonal imbalance, as we have just seen, can also be the cause of hormonal acne.

For this purpose, I have dedicated a section on "hormonal diseases" in this application that will give you expert advice for each pathology.

Again, I stress the importance of hormonal control through a gynecologist. It may take some time for the hormonal disorder to return to normal after the pill, this is normal.