Alopecia areata is a hair loss condition in which there is rapid loss of hair in round patches from some areas of the body. This is mostly experienced in the scalp. Though the cause of alopecia areata is unknown, it has often been linked with autoimmune diseases.
People who suffer from this condition are usually in good health. Of about one-fifth of people who develop alopecia areata, there is a family history of such a condition.
Causes of Alopecia Areata
There are several different hypotheses as to what causes alopecia areata.
1. Alopecia areata seems to have an autoimmune factor causing the patient to develop antibodies to different hair follicle structures.
2. Genetic factors play an important role as there is a higher frequency of a family history of alopecia areata in people who suffer from this condition.
3. cytokines, which are chemicals part of the immune system, may have a role to play in causing alopecia areata by inhibiting hair follicle growth.
4. Other studies show that emotional stress may also be the cause alopecia areata.
Why does hair loss occur in alopecia areata?
The reason why this happens is because the hair follicles telogen or late catagen stage of hair growth in a particular area. The hair follicles stop growing in the catagen stage and fall out on the telogen stage. In normal life, hair go through these stages randomly and the new hair growth outnumbers the hair that fall. But in this particular condition, all the hair in a particular area enter the catagen or telogen stage at the same time.
- Few studies are available regarding efficacy of intralesional steroids; however, they are widely used in the treatment of alopecia areata.
- Intralesional steroids are the first-line treatment in localized conditions.
- In a study including 84 patients, regrowth on treated areas was present in 92% of patients with patchy alopecia areata.
- In 61% of patients with alopecia totalis, regrowth persisted 3 months after the treatment.
- In 71% of patients with patchy alopecia areata and 28% of patients with alopecia totalis, regrowth usually is seen within 4-6 weeks in receptive patients.
- Patients with rapidly progressive, extensive, or long-standing alopecia areata responded poorly.
Types of Alopecia
Alopecia areata appears as a smooth bald patch, which at times may further expand in size. Similar patches may emerge later in other areas. Alopecia areata has been classified into several types according to the severity of the condition and its various forms.
- Alopecia Totalis: Under this condition, a person loses all the hair from the scalp.
- Alopecia Universalis: Under this condition, there is loss of all body and scalp hair including eyelashes, underarms, eyebrows and pubic hair.
- Alopecia Areata Barbae: This affects the hair of the beard region, and is known as alopecia areata barbae.
- Reticulated Areata Barbae: In this form of disease, there is hair loss in irregular patterns in a net like fashion but bald patches may not be found. In the scalp, there are regions of hair loss intersperse with areas with normal hair growth. There may be hair fall in one region but new hair growth in a different region.
- Ophiasis type of alopecia areata shows band like hair loss that mostly occurs in the temporal or the occipital regions of the scalp and is as a result more difficult to treat, as most medicines have a delayed action on these areas. It is recognized as a turban or snake like pattern on the outside edge of the scalp. Ophiasis means serpent in Greek and this is how the condition gets its name.
- Diffusion Type of Alopecia Areata: In this case, no distinct patches are evident. There is a early termination of anagen growth, which causes partial hair loss throughout the scalp. It may not be likely to identify the disease clinically, as it can easily be mistaken for telogen hair loss, which is hair loss caused by stress, certain physical conditions like puberty or childbirth, chronic illness, or trauma. It is also similar to hair loss in the anagen stage due to chemotherapy or radiation treatment. In a few cases of hair loss on top of the head, it also resembles distinctive male or female pattern of hair loss or even trichotillo in which people pull out their own hair. A biopsy is the best way to diagnose the disease distinctively. Dermatologists also look for the exclamation type of broken hairs as indication of alopecia areata.
- Perinevoid Alopecia Areata: This is a comparatively unusual type of alopecia areata in which spots of skin are found as having properties different from that of normal surrounding skin area. Patches having characteristics of alopecia areata are found around these pigmented spots or nevi.