What is dandruff?
Dandruff, which in medical terms is a squamous condition of the scalp, is an extremely common scalp problem. It involves a light, harmless desquamation of the epidermis of the scalp.
It should be noted that our epidermis, the outer layer of our skin, is continuously renewing itself. Every day, mature cells detach themselves from the skin. These are microscopic cells that fall away from the skin one by one, and we don't usually see them. However, in some skin diseases, this epidermal renewal is abnormal, and it occurs too quickly and excessively. Clumps of skin cells, visible to the naked eye, detach themselves from the scalp. These are called "squamae". Dandruff is therefore a visible manifestation of excessive scalp desquamation.
The hair itself isn't affected: dandruff conditions, though intense and long lasting, do not trigger hair loss.
What causes dandruff?
The main cause of simple dandruff, besides desquamative diseases of the scalp, is a microscopic fungus belonging to the yeast genus, called Malassezia.
Malassezia are usually present in small quantities on a healthy scalp. They develop excessively when their environment is rich in lipids. This is the case for the scalp, the center of the face and the upper torso, where sebaceous glands are highly abundant.
Besides the excessive presence of Malassezia, several factors can trigger the appearance of dandruff, or worsen it: stress, fatigue, hyperseborrhea of the scalp, scalp irritations (intolerance to hair products for example) and certain scalp diseases such as psoriasis, atopic dermatitis, certain eczemas and seborrheic dermatitis.
Different types of dandruff
Unattractive but harmless, this type of dandruff causes very small (1 to 2 mm) fine, white or light gray flakes to cover the entire scalp (which is dry and dehydrated) giving it a "dusty" appearance. These flakes detach themselves easily and fall "like snow" onto the shoulders.
This condition is sometimes accompanied by itching and moderate redness.
Squamae are associated with hyperseborrhea and are joined to the sebum. The sebum is eroded by the malassezia, causing redness and itching.
Big, thick, yellowish flakes of dandruff cling to the scalp.
For the skin
All conditions require the help of a health professional for diagnosis and treatment