Updated 11 February 2021
Hair GrowthBefore getting into what hair loss is, it is important to understand how your hair grows. Typically, your scalp consists of hair follicles (as many as 100,000) which serve as conduits from which hair grows out from your scalp. Your hair grows in three basic phases. The first is known as the follicle (anagen) growing stage where new hair starts growing from your hair follicles. This phase can vary in terms of the length of time for new hair to grow out from the follicles and the average length of time is 3 years. The second phase is known as the catagen stage which is really a transitional phase between the anagen stage and the telogen (this is the resting stage consisting of mature or fully grown hair with root). This second phase can take between one to two weeks. The third stage is the telogen phase where fully-grown hair with roots is loosely held by the follicles. This phase can last for between 4 to 5 months before the mature hair falls off. It is estimated that an average of 100 telogen phase hairs falls off from the scalp of human beings on a daily basis.
So what is hair loss?It is absolutely normal for a considerable amount of hair to fall from your scalp on a day-to-day basis. However, there are instances when this loss of hair may seem excessive and abnormal. Hair loss, which is also known medically as alopecia, occurs when you lose body and/or scalp hair at a rapid, excessive, and seemingly abnormal rate. This hair loss can be due to several reasons, for example due to scarring or disease. Hair loss may also be diffuse or localised in nature like balding. Alopecia could be as a result of hair thinning, poor hair quality and/or rapid hair shedding. Whatever is causing you to lose hair, finding a resolution may be difficult. Hair loss can affect anyone and that includes young children and adults, or males and females. Alopecia affects people of all races, as well as hair types, textures, and hair colours. Hair loss may be a temporary condition, for example hair loss during chemotherapy. Alopecia can also be a permanent condition, for example balding.
Common Signs of Hair LossThe most common signs of hair loss include;
- Localised balding,
- Excessive hair fallout when combing or brushing,
- Weak and loose hairs on the scalp,
- Inflammation of the skin, which may cause itching, redness and soreness,
- Hair shedding, which may be accompanied by trichodynia, a prickly, burning sensation.
Causes of Hair LossWhile hair loss is not contagious, it may be hereditary with people genetically predisposed to baldness. There is also androgenetic alopecia or pattern hair loss that may be due to hormonal changes. This form of hair loss is quite common and it is estimated that one-in-two people over 50 years of age would have pattern alopecia.
Anagen Effluvium:Anagen effluvium, otherwise called anagen hair loss, occurs when anagen phase hair is broken-off or tapered. This form of hair loss is caused by any of the following:
- Autoimmune disease,
- The use of certain medications such as chemotherapy or cytotoxic drugs,
- Anagen syndrome, which is a condition that is congenital in nature and characterised by empty follicles and shortened tapered/broken hairs.
Telogen Effluvium:Telogen effluvium or telogen hair loss is an excessive loss of telogen phase hairs. This condition may be caused by:
- Weight loss,
- Psychological stress,
- Surgical procedure,
- The use of certain medications such as anticonvulsants, anticoagulants, and contraceptives.
- An abnormal hair shaft,
- Tinea capitis which is a localised fungal infection,
- Localised skin infections like atopic dermatitis, cutaneous lupus erythematosus, and psoriasis,
- Deficiency in thyroid hormone,
- Deficiency in iron,
- Abscess, boils and other bacteria infections, and
- Herpes zoster (shingles) which is a viral infection.
How is Alopecia Diagnosed?Diagnosing alopecia would usually entail a physical examination and a review of your medical history by your physician. Your doctor may also perform a series of tests, such as:
- A hair pull test - this is done by pulling your hair in order to work out the percentage of telogen to anagen hairs,
- Swab test - your doctor may take pustule swab samples for microscopy, especially if microorganisms are suspected to be responsible for your hair loss,
- A wood lamp checkup,
- Scraping of the skin for the purpose of mycology,
- Blood testing to check for serology, thyroid function and haematology.