Hair loss is very common both in women and in men among all age groups. The problem affects 2/3 of the male population and a significant number of women. Hair loss is associated with severe discomfort and therefore enormous resources are allocated to the development of an effective treatment against hair loss worldwide. Hair is formed in the hair follicle and grows to form a long fiber. There is an average from 100 to 150 thousands of hair on human head. Human hair does not grow continuously. Growth cycles are separated by periods of rest. There are three basic phases of hair growth: anagen phase – intensive growth, catagen phase – transition stage and telogen phase – resting phase. Most hair (85-90%) on a healthy human head is in anagen phase. This is the phase when due to active divisions of cells of the root a hair shaft strongly attached to the matrix is formed inside the hair follicle. The rate of hair growth is approximately 1 cm per month. The length of a hair is dependent on the length of the anagen phase. Its duration varies typically from 3 to 8 years and is individual. After the growth phase is completed, there is a catagen phase (stagnation), associated with radical morphological changes (follicle begins to shrink). This phase usually lasts from 2 to 6 weeks. After this period of time telogen phase begins, leading to the hair falling out. This is accompanied by the disappearance of blood vessels around the hair bulb and hair follicle. This phase lasts from 2 to 5 months. After the hair falls out, the follicle is not damaged but returns to the growth phase again and the cycle is repeated. Unlike most mammals, human hair grows asynchronous. Growing, resting and shedding hair are distributed randomly. On a healthy scalp about 10% of hair is in a resting phase, so falling of about 100 hairs per day is normal and only noticeable when washing or combing hair. Losing more than 100 hairs per day should raise concern.
Causes of hair loss
Due to the fact that the growth, rest and re-growth cycle of hair involves many factors, there are numerous situations that may disturb this cycle. The most common cause of hair loss is male pattern baldness called androgenic alopecia. It affects not only men (read: hair loss in men) but also women and is caused mainly by two factors: progressive miniaturization of hair follicles and presence of male hormones (androgens). Male pattern baldness varies in men and in women. In men it usually starts as a temporal hair loss, followed by hair receding from the crown. This area becomes more pronounced with time and hair remains only on the back of the head, the occipital part of the head. In women, androgenic alopecia is diffuse on all areas of the scalp. It is manifested as significant thinning of the hair and is observed particularly in menopausal women. In androgenic alopecia growth phase of a hair is shortened, which leads to shortening hairs in subsequent cycles. At the same time, the falling out phase and the period between telogen phase and the beginning of the next cycle are prolonged. This process is associated with activation of the hair androgen receptor by dihydrotestosterone (DHT). DHT is a testosterone metabolite, produced by testosterone 5-alpha-reductase. The presence of DHT causes progressive miniaturization of hair follicles. Hair is getting thinner and less stained. Follicle size decreases with each cycle. The action of androgens on hair follicle also increases the activity of sebaceous glands, resulting in excessive production of sebum.
Other types of alopecia are usually temporary and related to factors such as: some medications, autoimmune diseases (alopecia areata), hormonal changes (e.g. postpartum), infections, trauma, stress or deficiency of nutrients, vitamins and trace elements. Alopecia aerata is an excessive hair loss of a suspected autoimmune mechanism. It may affect all age groups and is usually characterized by sudden onset. Alopecia areata presents as oval patches of hair loss appearing on the scalp, sometimes in more than one area. Reversible types of diffuse hair loss are also anagen and telogen effluvium. In anagen effluvium there is an acute damage to the hair follicle, e.g. during chemotherapy or radiotherapy and results in sudden loss of structurally damaged hairs. Hair loss usually occurs few days or weeks after the inciting cause and hair regrowth is usually spontaneous after cessation of the cause. In telogen effluvium the damage is less significant and is highly associated with experiences and diseases affecting the whole body, e.g. high fever, post-traumatic stress. Causative factor causes increased number of hairs entering the telogen phase. Excessive hair loss is usually observed after 2 to 5 months.
Whatever the cause, excessive hair loss is associated with progressive miniaturization of hair follicles, insufficient nutrition and frequently accompanying inflammation of the scalp. Often, hair loss is perceived as an incurable disease, the order of things. However, hair loss can be prevented.
Can hair loss be prevented?
Excessive hair loss is a problem affecting a large part of the population. Contrary to common belief, hair loss can be effectively prevented. In order to reduce hair loss, comprehensive approach to stimulate the activity of hair follicles and reduce inflammation of the scalp should be taken. Innovative comprehensive line of hair care products for excessive hair loss is dermena®. dermena® product line strengthens hair follicle, reduces hair loss and stimulates regrowth.