Part 1: The Causes of alopecia areata
Alopecia areata is a localized, patchy, non scarring type of hair loss, characterized by the presence of one or more round or oval hairless patches. The affected skin appears normal and smooth, unlike the fungal infections, where there is crusting of the skin and uneven breaking of hairs. On the periphery of the patches, a few short hairs, which taper and loss pigment as they approach the skin, may be seen. These are called “exclamation mark” hairs due to their resemblance to the mark.
Alopecia areata usually affects the scalp. Other hair bearing areas, especially the beard are also affected. Any age can be affected in alopecia areata; though the common age group is 15-30. The youngest alopecia areata patient I have seen was a 2 year old girl.
Causes of alopecia areata:
Autoimmune theory: Alopecia areata is thought to be an autoimmune disease where the body produces antibodies (‘auto’antibodies) against the hair germinal cells and cause their destruction in localised areas. The localisation of lesions also point towards a neural pathway involvement. In patients with graying hairs, it is common to see that only the black hairs fall off in the patches. Sparing of the grey hairs in alopecia areata indicates that normal nerve supply and melanin pigment is necessary for the alopecia areata to occur.
- Direct pressure: Many patients get patchy hair loss following direct pressure on hair bearing areas, e.g., from a tight fitting helmet, pressing the head against bed rails for prolonged duration while watching TV etc.
- Mobile phones and alopecia areata: Another complication of the modern device! Before the hands free sets became common, a number of patients, especially those using cheaper brands of cell phones, presented with alopecia areata on their beards. Possibly the radio waves emitted by the mobile phone damaged the hair follicles and triggered an autoimmune inflammatory reaction in the area. Most of them also had dull aching pains in their ear on the same side.
- Caries tooth: This is a very important factor usually ignored by patients and their doctors alike. In the Middle East where I practice, there is a very high incidence of alopecia areata. In my practice, I come across almost 6-7% alopecia cases among the total skin diseases. In addition to stress, one common factor that I noticed was the presence of caries tooth in almost all cases with recurrent patchy hair loss, especially on the beard. Research showed that alopecia areata of dental origin has indeed been mentioned in scientific journals.
Personally I make a habit of referring all my alopecia areata patients who come with recurring patchy loss of hair, especially resistant to treatment, to a dental surgeon. Most such patients stop getting recurrences after their teeth infection is taken care of.
Possible explanation of the relationship between caries tooth and alopecia areata: Tooth germinal cells and hair germinal cells have embryological and histological similarities. Hence, the antibodies forming against damaged tooth germinal cells and the bacteria attacking them must be affecting the hair follicles as well. This is only a hypothesis and need to be studied further. The involvement of nail (nail pits) in alopecia areata supports this hypothesis, as nail is another integument of the skin that is similar to the tooth and hair!
- Stress: Most patients who come with recurrent episodes of alopecia areata also report a preceding period of intense stress in their life. How the stress causes hair loss only in localized patches, is however, not known. Hypothetically the nerve supply and altered immune responses in stress may be playing a role in the causation of alopecia areata. Corroborative studies where cure has been affected following implementation of stress management techniques in non responsive patients point to a positive role of stress in the causation of alopecia areata.
Other Articles on Hair Loss
- Alopecia : Types and Causes
- How to Diagnose the Exact Cause of Alopecia or Hair Loss?
- How to Treat Hair Loss
- How to Manage Hair Loss in Females
Published by Dr Hanish Babu, MD on 10th June, 2018
The information given in this article is for educational purpose only so that patients are aware of the options available. No diagnosis should be made or treatment undertaken without first consulting your doctor. If you do so, the author or the website will not be responsible for any consequences. The images provided are for illustration purpose only and are copyrighted.
Copyright 2018 © Dr Hanish Babu, MD
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