Alopecia

Alopecia consists of a decrease in hair density or hair loss, in one section of the head or in several areas, and is either temporary or permanent.

It is one of the most common diseases of the hair follicle and a very frequent reason why visits are made to both primary care facilities and the dermatologist.

Types of alopecia

Although there are many types of alopecia, the most frequent are the following:

• Androgenetic alopecia (AGA) or common baldness is the most frequent form of alopecia.
• Alopecia due to telogenic effluvium; this consists of a widespread loss of hair and can be associated with seasonal changes, thyroid diseases, hormonal factors, etc.
•  Alopecia due to anagen effluvium, generally presents as a widespread, sudden and intense loss of hair that appears a few days after the triggering cause (diseases, infections, anti-tumour agents, zinc or essential fatty acid deficiencies, etc.).
• Alopecia areata, characterised by the presence of one or more hairless patches, typically located on the scalp but also affecting the eyebrows, eyelashes, beard, etc.

Androgenetic alopecia

Hair loss known as common baldness or androgenetic or androgenic alopecia is due to a genetic susceptibility that strengthens the action of the testosterone hormone in the hair follicles in certain areas.

In Spain, 63% of 50-year-old men have male androgenetic alopecia (MAGA), which is an amount that increases with age.

On the other hand, 36% of women suffer from female androgenetic alopecia (FAGA), which is usually accentuated after the menopause due to the loss of estrogenic protection. In a high percentage of cases there is a family history, although there are also some factors that may aggravate the tendency toward alopecia, such as an iron deficiency.

Treating androgenetic alopecia

There are three types of treatment for androgenetic alopecia: topical, oral or surgical. The doctor must determine which is the most appropriate treatment or combination of treatments for each patient.

The most widely used topical treatment for androgenetic alopecia is minoxidil, a topical drug that has a vasodilatory action that has shown to increase the duration of the anagen phase (hair growth phase) and the size of the hair follicles. The effects of the increase in hair density can be seen between the 4th and 6th month of treatment.

Although there are other medications, the most widely used one for treating androgenetic alopecia orally is finasteride. This prescription medicine acts as a 5α-reductase type II inhibitor and decreases the conversion of testosterone to 5DHT (triggering the phenomenon of the miniaturisation of hair follicles). Finasteride also increases the number of hairs, their length and thickness. These changes become evident after 4-6 months of treatment and are sustained for however many years the treatment lasts.

Finally, surgical treatment is mainly based on autologous hair transplantation, although there are also other types of operations.