Hair shedding is actually a very normal situation of simple metabolism. The amount of hair loss is related to the growth phases. Under normal circumstances, 90 - 95% of hair is in growth phase, 5 - 10% in resting phase, and less than 1% in degradation. Any factors that interfere with these phases will alter the cycles. If the amount of hair in the growth phase is decreased, while those in the degradation and resting phases is increased, then more hair will be lost.
On average 50 - 100 telogen hairs are shed every day. This is normal hair loss and accounts for the hair loss seen every day in the shower and with hair combing. These hairs will re-grow. A variety of factors can affect the hair growth cycle and cause temporary or permanent hair loss (alopecia) including medication, radiation, chemotherapy, exposure to chemicals, hormonal and nutritional factors, thyroid disease, generalized or local skin disease, and stress.
Only when the number of hair shed each day is far more than 100, then hair thinning or balding will occur.
Hair loss can be divided into Generalised and Localised causes.
Generalised Hair Loss
- Androgenic Alopecia
- Telogen Effluvium
- Drugs
- Thyroid Diseases
- Iron deficiency
Androgenic Alopecia
This is the most frequently encountered situation and will be discussed in the next section.
Telogen Effluvium
This is because all the hairs suddenly enter into the degradation phase, and then all are shed. This usually happens in cases of acute severe illness, or the first 3 months after pregnancy. Other causes include major surgery, or extreme fasting such as anorexia. This causes a great alarming concern, but is only temporary, and will return to normal after a certain time. No treatment is necessary.
Drugs
Many drugs can lead the hairs into the degradation phase, and subsequent falling. This usually happens in a few weeks after starting the drugs, and returns to normal in a few months after stopping them.
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Examples: |
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Blood thinning drugs |
Heparin |
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Warfarin |
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Psychiatric drugs |
Amitriptyline |
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Lithium |
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Haloperidol |
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Anti-epileptics drugs |
Carbamazepin |
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Anti-inflammatory drugs |
Indomethacin |
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Anti-thyroid drugs |
Carbimazole |
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High blood pressure drugs |
B-blockers |
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Vitamin A derivatives |
Retinoids |
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Anti-parkinson drugs |
L-Dopa |
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Bromocriptine |
Majority of these medications are prescribed because they are necessary, and therefore it may not be possible to discontinue them. If they are suspected to be causing the hair loss, do not just stop them, but seek the doctor’s advice.
It is commonly known that chemotherapy for treating cancers will cause total hair loss. This is because the chemotherapy will target any high-growing cells, including the continually splitting cells in the hair bulb. The hair will grow back after the chemotherapy is stopped.
Others
Throid problems, either over or under activity, chronic liver diseases, and iron deficiency can all cause a generalised hair loss. When the problems are corrected, the hair loss will slowly return to normal too.
Localised Hair Loss
- Alopecia Areata
- Trichotillomania
- Traction Alopecia
- Tinea Capitis
Alopecia Areata
Please go to the following sections.
Trichotillomania
This is due to uncontrolled and un-aware repeated pulling and twisting of the hair, causing the hair to be broken at different lengths, but not to the stage of balding.
It usually happens in children and adolescents, because of some psychological upset. The sufferers will deny this behaviour. What needs treatment is their psychology.
Traction Alopecia
This is due to unsuitable method of hair styling, for example when the hair is pulled back too tightly into a ponytail over along period of time will cause hair loss in the front hair margin.
Tinea Capitis
Please go to the following sections.