Psychogenic hair loss results from excessive mental stress. Under stress, the arrector pili muscles contract, causing hair to stand erect while constricting the capillaries supplying nutrients to hair follicles. This impairs local blood circulation, altering the hair's ecological balance and leading to malnutrition.Psychological stress can also trigger excessive sweating and sebaceous gland overactivity, producing scalp buildup that degrades the hair's living environment and contributes to hair loss. This type of hair loss is temporary and typically resolves spontaneously with improved mental well-being and reduced stress.
Androgenetic Alopecia
Androgenetic alopecia, also known as early baldness or commonly called "going bald," has a relatively high incidence rate. It refers to the progressive thinning and loss of hair that begins in adulthood, characterized by rapid receding temples, a highening frontal hairline, and thinning or even complete baldness on the crown.This condition is characterized by progressive hair loss in the forehead and crown areas, commonly observed in men engaged in intellectual work. Symptoms typically emerge between the ages of 20 and 30. Hair loss generally begins at the forehead and temporal regions, with the frontal hairline gradually receding backward.creating a higher forehead. With age, hair on the crown gradually thins, though hair often remains at the back and sides. In severe cases, hair loss on the crown and forehead may merge into a large bald area, leaving only a horseshoe-shaped band of hair around the edges. The affected skin may be smooth or retain sparse, fine, soft hairs.Androgenetic alopecia progresses slowly. Female patients typically experience milder hair loss, most commonly thinning hair on the crown that becomes finer and softer. This form of baldness affects appearance in both men and women. Its causes may involve genetics and androgens. This type of hair loss is generally permanent.
Seborrheic Hair Loss
Seborrheic hair loss occurs against a background of excessive sebum secretion, often accompanied by increased dandruff, greasy scalp, and noticeable itching. It predominantly affects young to middle-aged adults with active sebaceous glands, typically presenting with fine, soft hair. Some cases may involve seborrheic dermatitis of the scalp. Hair loss begins gradually at the crown and may spread to the forehead.The scalp appears greasy, shiny, and reddish, with yellowish oily crusts forming. Treatment for seborrheic alopecia must prioritize hair care: reduce consumption of greasy and spicy foods, wash hair frequently, and apply topical medications to remove oil, reduce dandruff, and alleviate inflammation and itching.
Alopecia Areata
Commonly known as "ghost shaving," alopecia areata is a localized patchy hair loss that occurs abruptly and progresses slowly. Causes may include temporary suppression of hair growth due to neuropsychological factors, endocrine disorders, or immune dysfunction.Infections or other internal organ disorders may also be associated. It manifests as sudden circular or oval patches of hair loss on the scalp, often without noticeable symptoms, leaving the affected area smooth and shiny. As the condition progresses, the patches expand, with surrounding hair becoming loose and easily shed. In some cases, all hair may fall out, and severe cases may involve loss of eyebrows, facial hair, underarm hair, or pubic hair.This condition may resolve spontaneously but often recurs, with the disease course lasting several months or longer. New hair growth during recovery appears fine, soft, and grayish-white, gradually thickening and darkening to normal color. Treatment for alopecia areata involves identifying potential causes, followed by psychological counseling and other therapeutic approaches. This may be supplemented with oral and topical medications.
Physical Hair Loss
This category includes mechanical hair loss such as styling-induced hair loss and localized friction-induced hair loss, as well as burn-related hair loss and radiation-induced hair loss. Mechanical baldness occurs when specific hairstyles cause hair breakage or loss. Examples include braids and buns in women, and parted hairstyles in men.Hair requires a degree of natural volume and elasticity to withstand pressure. Direct tension, like that experienced by Peking Opera performers or female athletes who pull hair back tightly with ribbons or elastic bands for performances or competitions, can cause breakage and loss at the forehead, leading to a receding hairline.Excessive exposure to ultraviolet rays in sunlight and frequent use of hot blow dryers can also thin hair. Radiation damage is clinically classified into four degrees, all of which can cause hair loss.>Chemical Hair Loss
Cancer patients undergoing chemotherapy, as well as long-term use of certain chemical agents like commonly prescribed gentamicin, allopurinol, methimazole, thiouracil, trimethadione, propranolol (Inderal), phenytoin sodium, aspirin, indomethacin, and birth control pills, frequently cause hair loss.Hair care products like perm solutions, shampoos, and hair dyes are also common causes of hair loss. In recent years, the incidence of thinning hair among women has increased, potentially linked to irresponsible advertising promoting excessive use of shampoos.
Symptomatic Hair Loss
Conditions such as anemia, liver or kidney disease, malnutrition, systemic lupus erythematosus, Sjögren's syndrome, acanthosis nigricans, and febrile illnesses like typhoid fever, pneumonia, meningitis, or influenza often lead to hair loss and thinning. This type of hair loss is termed symptomatic hair loss.
Nutritional and Metabolic Hair Loss
Excessive sugar or salt intake, protein deficiency, iron or zinc deficiency, excessive selenium, and certain metabolic disorders like argininosuccinic aciduria, homocystinuria, hereditary lactoacidosis, and methionine metabolism disorders can also cause hair loss.Sugar-induced hair loss: This occurs due to excessive sugar consumption. During metabolism, sugar generates large amounts of free radicals that deplete B vitamins and disrupt pigment metabolism in hair, gradually causing hair to lose its black luster and turn dry and yellow. Excess sugar also increases sebum production, potentially triggering seborrheic dermatitis on the scalp, leading to significant hair loss.Salt-Induced Hair Loss: This type of hair loss results from excessive salt consumption. Salt causes water retention in the body, including within hair follicles, disrupting normal hair growth. Additionally, high salt levels in hair create an ideal environment for bacterial growth, increasing susceptibility to scalp conditions. Excessive salt intake can also trigger various sebaceous disorders, leading to increased dandruff and exacerbating hair loss.
Infectious Hair Loss
Hair loss caused by fungal infections, parasites, viruses, or suppurative skin diseases is termed infectious hair loss. Conditions such as scalp chickenpox, herpes zoster virus, human immunodeficiency virus (HIV), Mycobacterium leprae, Mycobacterium tuberculosis, Treponema pallidum, and various fungal infections like tinea capitis can all lead to hair loss.Localized skin conditions like seborrheic dermatitis, lichen planus, fungal infections, or parasitic infestations may also cause hair loss.
Endocrine-Disordered Hair Loss
Hair loss resulting from hormonal imbalances due to abnormal endocrine gland function is termed endocrine-disordered hair loss.Postpartum periods, menopause, and oral contraceptive use may temporarily cause estrogen deficiency and hair loss. Conditions like hypothyroidism, hyperthyroidism, hypopituitarism, hypoparathyroidism, adrenal tumors, and advanced acromegaly can all lead to hair shedding.