Alopecia androgenetica in men L64.-

Most common type of hair loss realized by androgens in men and women. Emergence of the genetically determined characteristic pattern of the hair coat. Frequently accompanying seborrhoea (hence also Alopecia oleosa, Alopecia seborrhoica).

Prevalence in European men up to 80%; prevalence in Asian & African men low.

• Associations with polygenic hereditary factors are discussed, which are unknown so far. Genes involved in androgen-hair follicle interaction are likely. Described in connection with alopecia are, among others, the hairless gene (see also Alopecia congenitalis universalis) and the androgen receptor gene (AR gene), which is localized on region Xq12-22 of the X chromosome. Possible associations with A. androgenetica are still controversially discussed.
• The interaction of genetic predisposition and hormonal manifestation factors leads to shortening of the anagen phase and miniaturization of hair follicles with vellus hair formation ("regressive metamorphosis"). Due to genetic predisposition, hair follicles express DHT receptors. Natural ligand of these receptors is DHT (dihydrotestosterone), which is formed by conversion of testosterone to DHT by the enzyme 5α-reductase. 2 isoenzymes of 5α-reductase are known: type 1 and type 2 (predominated in hair follicles of scalp & beard). Intracellular binding of DHT to DHT receptors results in the alteration of the androgen-receptor complex, which is transported to the nucleus and acts as a transcription factor. The distribution of androgen-metabolizing enzymes (5α-reductase type 1 u. 2, aromatase, hydroxysteroid dehydrogenase) is possibly responsible for the expression of androgenetic alopecia. In males, a 1.5-fold higher activity of androgen-metabolizing enzymes has been demonstrated frontally.
• Secondary factors (associations are controversial!):
  • Seborrhea
  • Cholesterol accumulation in the scalp (5α-reductase expression from cholesterol after contact with sunlight in the scalp!).
  • Circulatory disorders in the scalp.

Variable, usually before the 40th LJ; first signs often already after puberty, usually in the 3rd decade of life. Maximum in the 4th decade.

Variable clinic according to the stage of the disease:

• Stage I: Normal hair pattern.
• Stage II: receding of the forehead-hair borders, especially at the temples with formation of receding hairline.
• Stage III: Tonsure-like, occipitoparietal hair thinning with existing hair bridge.
• Stage IV: Almost complete loss of hair in the parietal region; remaining lateral and posterior hair crown.
• Stage V: Thin occipital and parietal crown-shaped hair.

Reminder. Treatment should take place as early as possible to stop irreversible follicular regression!

Guidelines Right 5% minoxidil solution or foam, internally 1 mg finasteride per day as a tablet. If not successful, 0.5 mg dutasteride per day.

Furthermore, if sufficient donor hair is available, hair transplantation by appropriately specialized surgeons can be recommended.

Currently, successes with low level laser therapy and injections of platelet-rich plasma from autologous blood (PRP) are described. For the latter two procedures, controlled clinical studies are still lacking.

In the case of a pronounced desire for therapy, detailed counseling and information about possible therapy options. It is important to dampen the usually too high expectations of a successful therapy. The primary goal of treatment is to stop the progression of hair loss.

Reminder. Important for all therapy approaches: Therapy successes can only be expected after several weeks to several months of application.

Therapy with Platelat-rich plasma (PRP) shows good results.

Soft lasers, which work with long-wave red light, can also stimulate hair growth.

ApplyMinoxidil 5% solution (e.g. Regaine 5%, Lonolox) 2 times/day to the affected areas. Continuous therapy required, as hair loss recurs in men after discontinuation, about 3 months later.

Caffeine-containing topicals: In vitro and penetration studies on the effect of caffeine on the hair follicle demonstrate penetration and accumulation of topical caffeine (Otberg N et al. 2008). However, penetration and accumulation are not synonymous with stimulation (Dressler C 2017).

Smaller predominantly positive studies exist on combinations of caffeine+minoxidil (Golpur et al 2013), caffeine (1.5%)+minoxidil (5%)+azelaic acid (1.5%) (Pazoki-Tourodi et al 2013).

Evidence on the effects of topical caffeine even in combination with other agents such as minoxidil and aelainic acid at the hair root is currently insufficient (Fischer TW et al. 2014). The European S3 guideline for the treatment of AGA mentions caffeine as a treatment option, but does not give an indication for treatment due to lack of evidence (cited in Dressler C 2017).

Thymuskin is reported to have shown a beneficial effect on hair growth in small study cohorts.

Finasteride locally as a spray at a dosage of 2.275 mg/ml for men with mild to moderate alopecia androgenetica (age range 18-41 years). Dosage starting with 1 Srpühstoß/day and daily increase by 1 spray up to 4 sprays / day on the light areas.

• Finasteride (e.g. Propecia®: 4-azasteroid = selective 5-alpha-reductase-type 2-inhibitor) 1 time a day 1 mg p.o. for at least 6 months ( off-label use; finasteride is available only on prescription but not reimbursable). Studies comparing finasteride with minoxidil show a significantly superior efficacy of finasteride (Arca E et al. 2004). It has been shown that finasteride is a long-term therapy approach (>6 months). Patients should be informed that possible therapeutic success will decrease if the therapy is discontinued.
• Alternatively, dutasteride (e.g. Avodart, selective 5-alpha-reductase type I and type 2 inhibitors): once/day 0.5 mg p.o. for at least 6 months ( off-label use).
• Please note the possible side effects caused by the antiandrogenic effect.
• Nicotinic acid p.o. (e.g. Nicobion Tbl.) and vitamin B-complex (without_B1) can be used as support.

If necessary, transplantation of mini- or micrografts from the occipital parts of the head, see hair transplantation. Donor dominance, micrografts 1-2 hairs, minigrafts 3-5 hairs. After 3-6 months normal growth should occur.

Notice! Artificial hair transplants are obsolete because of foreign body reactions!

Currently, further studies are expected in male androgenetic alopecia with extracts of green tea (epigallocatechin-3-gallate), extracts of saw palmetto fruit (Serenoa repens) as well as Citrullus colocynthis and Cuscuta reflexa (Rondanelli M et al. 2016).

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