Throughout human history, human hair has been perceived as a sign of strength, seduction and identity.
Alopecia affects a high proportion of the population.
Several causes and trigger factors exist.
Among the causes of acute alopecia one finds stress, post-natal loss, weight loss diets, surgery, fever or acute infection, haemorrhage, the taking of medicines and illness.
The factors responsible for chronic alopecia include: iron deficiency, dietary deficiencies, endocrine problems ( thyroid problems, hypoparathyroidism, and hypopituitarism ), kidney failure, hepatitis, connective tissue diseases ( scleroderma, lupus etc ).
Our head hair is a particular variety of hair. We possess about 80000 to 160000 hairs on our head. They renew themselves every 3 to 5 years following cyclical growth. In this cycle 85% of our hairs are in the anagen phase ( growth ), 1 to 2% in the catagen phase, and 15 to 20% in the telegen phase ( when the hair is lost).
Thus, physiologically, we lose between 25 and 60 hairs per day, with two seasonal peaks in the spring and autumn.
When the quantity of hair lost goes beyond this value we call it alopecia. It is acute alopecia if the loss develops over more than 3 months, and chronic alopecia if it develops over more than 6 months.