If you don’t want to be bald, please take care of it!

As the saying goes, "Your hair starts to fall out when you sit at home." Some people are born with a lot of hair, while others suffer from severe hair loss. Why do you start to lose your hair when you haven't done anything?

#1 Scalp and Hair

As the name implies, the scalp is the skin on the head. Like the skin on other parts of the body, it is located on the surface of the human body, and from shallow to deep, it is divided into the epidermis, dermis and subcutaneous tissue. The scalp not only has hair follicles, hair, sebaceous glands, sweat glands and other skin appendages, but also has abundant blood vessels, lymphatic vessels and nerves. The hair on it has functions such as protection and friction prevention. Hair is divided into two categories: vellus hair and terminal hair. Vellus hair is a short and soft hair that is usually without medulla and has no or little melanin. It exists on almost all smooth skin except the palms and soles. Most of what we usually call "sweat hair" belong to this category. Terminal hair is divided into short hair and long hair. Eyebrows, eyelashes, nose hair, and ear hair are generally less than 1 cm long and are classified as short hair; head hair, beard, armpit hair, pubic hair and chest hair are often more than 1 cm long and are classified as long hair.

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Like all body hair, hair is composed of keratinized epidermal cells. The part above the skin is called the hair shaft, and the part inside the hair follicle is called the hair root. The lower end of the hair root swells into a hair bulb, and the concave part at the lower end is called the hair papilla, which is the connective tissue that extends into the hair bulb. It contains blood vessels and nerve endings that provide nutrition to the hair bulb. The lower part of the hair bulb near the hair papilla is called the hair matrix, which is the growth area of ​​hair and hair follicles. The key to whether our hair is gray or black is the melanocytes in it.

From the inside to the outside, hair consists of medulla, cortex and hair cuticle. The medulla is the central part of the hair, which is composed of 2 to 3 layers of partially keratinized polygonal cells. Except for the ends of the hair, the rest of the hair has medulla. The medulla plays a role in regulating body temperature in the hair of animals. Although this ability of humans has degenerated, the air gaps in it can still prevent heat conduction to a certain extent. The cortex is the main part of the hair, which is composed of several layers of spindle-shaped keratinized epithelial cells, and the cytoplasm contains melanin granules. The cortex determines the elasticity, strength and flexibility of the hair. The hair cuticle and the sheath cuticle are tightly embedded with the help of serrated protrusions, so that the hair is fixed in the hair follicle.

#2 The alternation of old and new hair

The morphology of hair follicles changes with the hair growth cycle. The hair growth cycle includes the catagen phase, the resting phase, and the growth phase. The longest growth phase of hair follicles is about 3 to 4 years. Under normal circumstances, 85% to 90% of hair follicles are in the growth phase, 1% are in the catagen phase, and 10% to 14% are in the resting phase.

Image source: Pixabay

Of the 100,000 hairs on a person's head, about 60 to 100 will fall out every day. However, hair growth is actually a dynamic process. Hair grows while it falls out. Therefore, you don't need to worry about the hair on your pillow, on the floor, and everywhere in your home. Although they have left you, their brothers and sisters have "sprouted" without you noticing and will meet you again soon. This is the normal process of new hair replacing old hair.

#3 Is your scalp healthy?

A healthy scalp must ensure the normal secretion of scalp sebum. Too little scalp sebum secretion will make the hair dull, dull, and easily broken; if the sebum secretion is excessive, the hair will produce too much oil, which will also cause the hair to break and fall off easily.

The appearance of dandruff is not a sign of a healthy scalp. The formation of dandruff is mainly related to a fungus called Malassezia, and the oil secreted by the scalp is the "culture medium" of this fungus. These fungi can decompose oil and produce an acidic substance that stimulates the scalp to itch. Therefore, when your scalp is itchy and dandruff is falling like snow, your scalp is likely to be sick.

#4 Dandruff and Malassezia

Malassezia was originally discovered by French scientist Louis-Charles Malassez in the 19th century. Malassezia is a fungus that, like yeast, belongs to the yeast family. Like yeast, Malassezia is usually harmless and occurs naturally on the skin of humans and animals. Malassezia in humans requires oil to survive, while Malassezia pachydermatis in animals does not rely on oil to survive, but is also oil-loving. Because this fungus requires oil to grow, it usually infects areas with well-developed sebaceous glands, and the scalp is an area where Malassezia grows "densely".

If you have a lot of oil secretion, coupled with high temperature, humidity and other factors, Malassezia can also be a pathogen. Some young people with active metabolism, as well as those with hyperhidrosis and oily skin are more likely to get sick. When these fungi reproduce too quickly, the lipase secreted by the fungus decomposes lipids, producing non-esterified fatty acids that stimulate the hair follicles and surrounding tissues to produce an inflammatory response, disrupting the natural renewal process of cells, and causing itching and dandruff. Did you know? On the head skin of patients with Malassezia folliculitis, the number of this fungus can even exceed 10 million.

#5What should I do if my scalp is sick?

Malassezia folliculitis is a folliculitis skin disease caused by Malassezia. This disease is prone to occur in areas rich in sebaceous glands, such as the upper back, chest, shoulders, neck, etc. The skin lesions are often scattered follicular hemispherical red papules with a diameter of 2 to 6 mm, a shiny surface, a red halo around the periphery, or pustules, and itching symptoms.

If you have the above symptoms, then your dandruff and itching symptoms are likely caused by Malassezia. Of course, mycological examination is needed in the end. It is worth mentioning that there are almost no Malassezia bodies or spores in dandruff. Malassezia spores are mainly found in the openings of sebaceous glands and oily secretions of the skin. Therefore, you don’t need to worry about dandruff infectious bacteria. Even if you take a step back, Malassezia itself exists on the surface of healthy skin, so you don’t have to worry about infecting your family and friends.

Although the root cause is the excessive oil secretion, clinically, retinoic acid ester drugs are rarely used to control oil secretion for this disease. In most cases, it can be controlled by maintaining a regular schedule and controlling sugar and milk protein. If necessary, lotions containing selenium sulfide or ketoconazole can be used for antifungal treatment.

Source: Chongqing Science and Technology Museum

Review experts: Huang He, Li Chunli, Chen Tao, Xu Xiaoping

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