MALE PATTERN HAIR LOSS - WHAT CAUSES IT?

The enzyme 5 alpha reductase converts testosterone into dihydrotestosterone (DHT).

Exposure of hair follicles to DHT causes them to shrink, and when DHT is suppressed, hair follicles continue to thrive. In male pattern hair loss, there is an inherited sensitivity to DHT. These DHT sensitive hair follicles, on continuied exposure to DHT, begin to miniaturize, shortening their lifespan and resulting in hair loss.

Hair follicles in the sides and front of the scalp appear to be most sensitive to DHT, thus resulting in the typical pattern of male pattern baldness observed.

CONDITIONS WHICH CAN CAUSE HAIR LOSS

It is normal for the average person to lose up to 100 strands of hair each day through normal combing, brushing or washing of hair.  Excessive hair loss, however, may indicate some underlying condition.
A number of conditions are known to cause hair loss.  The more common conditions are listed below:

* Alopecia Areata
* Pregnancy and childbirth
* Hyperthyroidism and hypothyroidism
* Other hormonal problems
* Severe stress
* Major surgery
* Major infections or illness
* Autoimmune diseases, such as systemic lupus
* Fungal infections of the scalp
* Excessive pulling of hair - psychological or wearing of tight ponytails etc.
* Medication

MEDICATION WHICH CAN CAUSE HAIR LOSS

Many drugs can potentially cause hair loss.  With some, the hair loss may be minimal, whilst with others, there may be total hair loss (eg with chemotherapy drugs).  The good news is that, in most cases of drug-induced hair loss, it is reversible once the offending drug is stopped.

Drugs cause hair loss by affecting their normal growth cycle.

2 types of hair loss are recognisable:

1. Telogen effluvium

The offending drug causes the hair follicles to go into their telogen  ("resting") phase and fall out too early.  This usually appears within 2 to 4 months after starting the drug. This is a more common type of drug-induced hair loss.

2. Anagen effluvium

The offending drug prevents normal cell division (required for growth).  The matrix cells which are responsible for hair growth are also prevented from dividing normally. This type of hair loss occurs during the anagen ("growth") phase of the hair cycle, and the hair loss is experienced usually within a few days to weeks after starting the medication.  Chemotherapy drugs are well known to cause this type of severe hair loss, occurring in the scalp, eyebrows, eyelashes and other parts of the body.

Drugs Which Can Cause Hair Loss (not an exhaustive list)

* Oral contraceptives
* Retinoids (acne medication)
* Antibiotics and antifungals
* Steroids
* Thyroid medication
* Cholesterol-lowering drugs
* Psychiatric drugs eg. antidepressants, mood stabilizers
* Epilepsy drugs
* Hypertension medication eg. beta-blockers, ACE inhibitors, diuretics
* NSAIDS (non-steroidal anti-inflammatory drugs)
* Medication used to treat Parkinson's Disease
* Weight loss medication
* Drugs that suppress the immune system
* Chemotherapy drugs

You should consult your doctor if you suspect that your hair-loss may be due to some medication you may be taking.