Alopecia is the abnormal loss of hair in any of its locations. It also applies when, without actual loss, the patient notices a change in its quality such as brittleness, thinning or loss of volume. The causes are multiple and range from genetic – due to genetic or family predisposition of the affected person – to environmental – due to nutritional deficiencies in the diet or external aggressions.
To better understand the different causes, it is best to describe the different types of alopecia. Basically, alopecia can be divided into two main groups: scarring alopecia and non-scarring alopecia.
Scarring alopecia
These are rare, but may be due to:
- Congenital
- Caused by certain infectious agents.
- Caused by malignant tumors affecting the scalp.
- Due to other skin or general diseases, such as cutaneous lupus erythematosus, scleroderma, lichen planus, Brocq’s pseudopelade and folliculitis decalvans.
In these cases, fortunately rare, there is destruction of the hair follicle and residual cicatricial fibrosis, making full hair recovery more difficult.
Non-scarring alopecia: types and prevention
They are much more frequent and in them the chances of recovery are much greater because there is no definitive destruction of the hair follicle.
Within this group the most frequent forms are:
- Alopecia areata: this type of alopecia creates rounded areas of hair loss of variable size. It can appear at any age, although they are frequent in childhood. When the process affects the entire scalp it is called alopecia areata universalis. They are often associated with autoimmune processes, especially in the thyroid or emotional stress. In this case, it is best to intervene promptly if they do not tend to spontaneous resolution in order to try to prevent universal alopecia.
- Male and female androgenic alopecia: consists of a progressive thinning and loss of hair in the frontoparietal area of the scalp with receding hairline (receding hairline) that is progressive and can reach the crown area (vertex). It has a clearly familial character and in women it can appear after menopause, although in both men and women it can begin early during the first years of adulthood. It can be prevented by early initiation of appropriate treatment if the person recognizes the first symptoms early, especially if he or she has a family history of baldness.
- Diffuse alopecia: there are two main types: anagen effluvium and telogen effluvium. Anagen effluvium occurs a few days or weeks after the triggering agent – for example, administration of antineoplastic chemotherapy – and up to 90% of the hair can be lost. They are difficult to prevent although, in general, the prognosis is good and hair can be fully recovered.
Telogen effluvium occurs a few months after the responsible event -such as childbirth or an episode of high fever-, a hundred hairs are lost daily and it is more prolonged in time and can become chronic. A variant is seasonal telogen effluvium, which usually occurs in the autumn months after exposure of the hair to aggressive external agents during the summer months.
Treatments for alopecia
Treatments range from topical or intralesional corticosteroids in cases of alopecia areata, to the application of products approved by the FDA and the EMA for androgenic alopecia, such as topical or intralesional use of minoxidil and finasteride tablets at different dosages depending on the case. In general, our best advice is that if you have any doubts, you should consult a dermatologist you trust.