Because of hormonal changes in the body, damage or irritation, some hair follicles tend to have a shorter growth phase than their counterparts, and they tend to produce shorter, thinner, and weak hair shafts. Hair naturally goes through a growth and rest cycle, with each cycle varying from one individual to another. Generally though, anagen (the medical term for the growth phase of hair on the scalp), will last for a period of 2-3 years.
At this phase, hair will generally grow 1 centimeter (1/2 an inch) every month. Telogen (this is a medical term for the resting phase) will last for a period of 3-4 months. By the end of this phase, the weak hair strands will start to fall out as new and strong hair starts to grow. The moment hair is shed, a new growth phase will start and the cycle goes on and on.
Naturally, most people would shed at least 50-100 hairs on a day to day basis. With over 100,000 hairs in a healthy scalp, 50-100 hairs is an insignificant amount that can lead to a noticeable thinning of hair. Thinning, albeit at a gradual pace, is a normal and natural part of aging. Note however, that if no measures are taken it can lead to complete baldness, especially if the rate of shedding is more than the rate of hair re-growth. This can also be the case is the new hair that grows is thinner than the hairs that are shed, or in the event of patch hair loss.
Following are the specific types of hair loss and what triggers them.
Traction alopecia – this is a condition brought about by excessive styling of hair and wearing hairstyles that will pull the hair too tightly to a point of causing traction. Should you notice the effect and stop the pulling before there is permanent scarring on the scalp, or before there is permanent damage on the hair shafts and roots, natural hair will re-grow.
Telogen effluvium – this is a condition brought about by an abnormal change in the normal cycle of hair. This could be as a result of some kind of shock to the body system (mostly physical or emotional), which prematurely pushes/ forces the hair toots to transition into the resting phase. All affected hairs will definitely fall out. In about a month or two, the follicles will get active again and will trigger new hair growth. It is to be mentioned that hair in this condition will grow back once the underlying cause of the problem is corrected, but the process of new hair growth will take several months.