There are numerous types of hair loss classsification and many of them are indeed treatable/reversable. not all forms of hair loss are classified as male or female pattern baldness ( androgenic alopecia ).

Alopecia is a term used to describe all types of hair loss. there are 2 types of hair loss - scarring and non-scarring. scarring forms of hair loss usually prove permanent and do not usually allow for regrowth. infections that cause an inflammatory reaction around the hair follicle are usually associated with the scarring form of hair loss due to the fact that the follicle is usually replaced by scar tissue.

Deep bacterial/fungal outbreaks or the shingles virus can all be responsible. it is important that these conditions are treated at an early stage as residual follicular activity may then return. chemical or thermal burns ( including sunburn ) can all be responsible for causing scarring hair loss.

Male or female pattern baldness ( androgenic alopecia ) is the most common form of non-scarring hair loss. female pattern baldness is generally easier to treat than male pattern baldness where genetic sensitivity to sex hormones are usually to blame.

A condition known as telogen effluvium is a temporary type of hair loss caused by certain severe illnesses and types of medication. the key to limiting this type of hair loss is early consultation with a doctor/dermatologist. Medications than can be responsible for this type of hair loss include anti-depressants, anticoagulants, allopurinol, anti-inflammatory drugs, cancer treatments, birth control pills, hormonal treatments and steroids. Vitamin a can also cause this type of hair loss but only in very high doses. other types of hair loss are as follows :

Alopecia areata. this type of hair loss is characterized by coin-shaped patches of hair loss while surrounding hair appears normal. Although the exact cause of this condition is unknown, it is thought that an immune system condition may be responsible.

At times, the lost hair may return but reoccurences of the condition are common. if scaling accompanies the condition, it is possible that ringworm may be responsible. ringworm is easily treatable with antifungal medication.

Alopecia totalis. this condition is as its name implies, total loss of all bodily hair. this condition even affects areas such as the eyebrows.
Traction alopecia. this is a form of reversible hair loss. this condition is caused by tension being applied to the root of the hair caused by certain hairstyles such as ponytails, braiding or hair weaving on the scalp.

Trichotillomania. this is a compulsive disorder condition, more common amongst females where the sufferer pulls out their own hair. compulsive disorder medications such as luvox and anafranil are used to treat this condition.

The norwood hair loss scale invented by dr. norwood in the 1970's, illustrates the different degrees of male pattern baldness :

The progression of female pattern baldness is generally classified on the ludwig scale and is illustrated as follows :