Alopecia is the official name of this often emotionally charged problem. It has a multitude of causes, not all of which are irreversible, so managing the problem is definitely worth an in-depth evaluation of the sufferer's situation. Bear in mind that growing scalp hair is not a continuous process. Hair follicles have a growth phase (anagen) and a resting, non-growth phase (telogen). A loss of up to 50 hairs a day can be normal and does not necessarily mean that the follicles have forever ceased to produce hair.

True hair loss, whether partial or complete, is traditionally divided into two kinds: scarring and non-scarring. The scarring forms are less likely to allow for regained growth. However, early diagnosis is important, because some loss may still be at least partially reversed. Scarring forms usually involve infections that cause inflammatory reactions around hair follicles, which eventually are replaced by scar tissue; deep bacterial and fungal outbreaks or the herpes zoster (shingles) virus can all be responsible. If treatment comes early enough, residual follicular activity may return. Serious physical trauma, such as abrasive, chemical or thermal burns, can also cause scarring hair loss.

The most common form of non-scarring hair loss is male pattern baldness (androgenic alopecia), which may start at the peak of the skull or at the sides of the frontal region. Though not all the contributing causes are known, we know the sex hormones are involved. However, female pattern baldness is not at all uncommon, though it's not nearly as widespread as in men. Stopping female pattern baldness is more likely than stopping male pattern baldness.