The fundamental role of hormones in the development of acne cannot be ignored. Most of the androgens such as dihydrotestosterone (DHT) and testosterone, adrenal precursor dehydroepiandrosterone sulfate and estrogens are produced by the gonads and adrenal glands. Conditions of androgen excess or hyperandrogenism are associated with increased sebum production which in turn leads to acne formation. Thus, to counter this problem of excessive androgen, hormonal therapy that includes the use of anti androgens is recommended.

The role of androgens

That androgens are essential in the development of severe types of acne is explained by the fact that the onset of prepubertal as well as acne in women, which do not respond to traditional therapies, is associated with high levels of serum androgen levels. Many biological processes are involved in the pathogenesis of acne and androgens play a key role and stimulate sebum production. However, it is still not proved whether serum androgen, locally produced androgens or a combination of both are responsible for acne formation.

Anti androgens in hormonal therapy for women

Hormonal therapy is ideal for women with proven ovarian or adrenal hyperandrogenism, hirsutism, excessive sebum secretion and acne beginning in adulthood and worsening before periods, and acne which are severe and resistant to other forms of treatment. Hormonal therapy for acne involves using anti androgens or androgen receptor blockers as well as agents that inhibit androgen production from the ovary or the adrenal glands. Androgen receptor blockers like cyprotene acetate, spironolactone, flutamide and finesteride are used for severe acne associated with high levels of serum androgens. Anti androgens block the effect of androgens on the sebaceous gland.

Finesteride

DHT is the effector androgen that mediates sebum production. Dihydrotestosterone is approximately 5-10 times stronger than testosterone in its reaction with the functional androgen receptor which leads to acne production. This dihydrotestosterone is produced from testosterone within the peripheral tissues such as the skin by the action of 5 alpha-reductase enzyme. The activity of 5-alpha-reductase in sebaceous glands in skin is prone to acne especially in the facial area. It is greater than that in sebaceous glands in non-acne prone skin. This implies that due to this enzyme there is increased production of powerful androgens such as DHT within the sebaceous glands of the facial area which in a way points towards the development of acne in these particular areas.

Two isozymes of 5 alpha – reductase are identified. The type 1 is active within the sebaceous glands whereas the type 2 isozyme is most active in the prostrate gland in men. Finasteride is a specific inhibitor of the 5 alpha-reductase 2 enzyme, the enhanced activity of which leads to the development of androsterone and ultimately to the formation of severe acne in adult women. Hyperandrogenic women suffering form acne are sometimes treated with finasteride – though more so in Europe than in North America.

Finesteride has shown to be similar in effectiveness to other well-established anti-androgen treatments in hyperandrogenic acne. Moreover, only a very low dosage of 5 mg per day of this anti androgen receptor blocker is effective in acne reduction. In patients who respond well to treatment, acne improves rapidly and may even be thoroughly eliminated after two to three months.

Finasteride compared to other anti androgens

Finasteride is reported to successfully reduce acne lesions but total acne scores are reduced by approximately 36%, which is lower compared to another novel anti androgen flutamide. Even low doses of flutamide at 250 mg daily are observed to be as effective as cyproterone acetate in acne reduction and reduced acne scores by 60% in majority of patients. This may be explained by the fact that finasteride inhibits the 5 alpha-reductase 2 enzyme while acne development is associated mainly with 5alpha-reductase 1 enzyme.

Associated side effects

Despite its lower effectiveness compared to other anti-androgen drugs, finasteride is still used to treat androgenic acne. The risk of side effects from finasteride is much lower compared to flutamide, which is rarely used because of its significant side effect profile. Finasteride side effect risks are also somewhat lower than cyproterone acetate.

Finasteride is well tolerated. No side effects are observed with the dosage of 5 mg finasteride used daily. Finasteride does not have any effect on the pattern of menstrual flow and neither does it affect the blood glucose level or liver enzymes of women treated with this drug.

However, since finasteride is an anti androgen, women who are using this drug but wish to get pregnant should stop using the drug. Getting pregnant when using finasteride will result in significant developmental defects in the embryo. When women of child bearing age are given finasteride by dermatologists, they are also required to use oral contraceptives to prevent pregnancy.

So all said and done, finasteride though less beneficial or effective compared to the antiandrogen flutamide is still an effective androgen receptor blocker and is successful in treating severe androgenic acne even at a lower dosage of 5 mg per day.