Hair is an annex of the skin that covers much of our body. It is formed by the root and the stem. The root is the part that remains inside the skin and arises from the hair bulb that is in small holes in the dermis: hair follicles . The stem is the part of the hair that is visible above the skin. The hair is distributed along regular lines that are called rivers and that are located around eddies. The easiest swirl to see is the one we have at the apex of the head. The hair root is in contact with a small erector muscle that is the one that stresses the hair producing the effect that we popularly know as “goosebumps”.
We all lose about 50 hairs a day in a normal regeneration process, which has no consequences because they are renewed with follicles that are in the growth phase. When hair loss is excessive and does not recover we find a situation of alopecia that leaves less density or absence of hair in some area of the head.
The Alopecia in Male
The most frequent male alopecia is the androgenetic. They suffer, to a greater or lesser extent, 50% of men over 30 years of age and that percentage increases with age. It has a typical pattern in men that starts at the temples and continues in the frontal area and in the crown.
The Alopecia in Female
Female alopecia has a more heterogeneous origin than in men, although its main cause is also androgenetic. In women, the percentage of involvement before the age of 45-50 is lower and, on the other hand, it is accentuated with the onset of menopause. Female androgenetic alopecia does not generate defined areas of baldness but produces areas of lower hair density, especially in the upper area of the head.
There are other specific causes that cause hair loss and that we must differentiate for a correct diagnosis and treatment.