Androgenic alopecia (baldness, hair loss)
What is it?
The androgenic alopecia or male baldness is a physiological event that occurs in genetically predisposed individuals, not considered a disease. Genetic background may come from the paternal or maternal side.
The alopecia is the result of stimulation of hair follicles by male hormones which begin to be produced during adolescence (testosterone). Upon reaching the scalp of patients with a genetic tendency for baldness, testosterone undergoes the action of an enzyme called 5-alpha reductase and is converted into dihydrotestosterone (DHT).
It is DHT that will act on the hair follicles promoting their progressive decrease with each cycle of hair growth, which become smaller and thinner. The end result of this process of reduction and thinning of the hair is baldness.
Characteristics and symptoms
The main feature is the continuous decrease of hair with the replacement of yarns each time thinner and shorter until the cessation of growth, pushing the front line to the back.
The progression leads to baldness, characterized by the absence of hair on top and front of the head, sparing the lateral and posterior areas.
Increased production of sebum and dandruff may also be present accompanying the process of hair loss, but are not responsible for baldness.
Women with normal hormone levels may also be affected, but not enough to undergo baldness, presenting diffuse rarefaction of hair which also becomes thinner. Generally, these manifestations worsen after menopause.
Treatment aims to prolong the life of the hair follicles by slowing or stopping the process of hair loss. It can be done through the use of substances applied directly to the scalp, such as minoxidil, or with oral medications such as finasteride.
Finasteride has revolutionized the treatment of androgenic alopecia because it blocks the enzyme action that gives rise to DHT. The medication is effective in controlling hair loss in most patients and even promote reversal of vellus hair (fine and small) into normal hair, characterizing hair regrowth (below).
- Alopecia areata
- Seborrheic dermatitis