Hairloss Glossary of Terms

Alopecia areata is a condition where the immune system mistakenly attacks the hair follicles, leading to patchy hair loss. It can happen anywhere on the body but is most often seen on the scalp. The term “alopecia” refers to hair loss or baldness, while “areata” indicates that the hair loss happens in small, random patches.

Alopecia totalis is a condition where someone loses all the hair on their scalp. It’s a more severe form of alopecia areata. While most people with alopecia areata only lose patches of hair, those with alopecia totalis experience complete scalp hair loss.

Alopecia universalis is a condition where a person loses all the hair on their scalp and body. It is a severe type of alopecia areata. While the exact cause of alopecia universalis isn’t known, it’s believed to be an autoimmune disorder. This means the immune system, which usually protects the body, mistakenly attacks the hair follicles instead.

Anagen effluvium is when hair suddenly falls out because the hair is in its growing phase. This happens when something disrupts the normal activity of hair follicles. It can be caused by chemotherapy, radiation, exposure to toxic chemicals, or certain diseases like alopecia areata and pemphigus. While hair usually regrows after one to three months, in some cases, this hair loss can be permanent.

Hair growth happens in stages, starting with the anagen phase. This is the longest phase, lasting anywhere from three to five years for the hair on the head. Different types of hair have different anagen phases. During the anagen phase, hair follicles produce hairs that grow until they’re cut or naturally fall out when their lifespan ends. About 90% of the hair on our heads is in the anagen phase at any given time.

Androgenetic alopecia is a common genetic condition that causes hair loss in both men and women. This happens because of a strong reaction to androgens, which are hormones in the body. About 50% of men and women experience this condition, often starting any time after puberty. In men, hair loss usually occurs at the top and front sides of the head. For women, the front hairline is generally unaffected, but hair thinning happens on the top and crown of the head, often creating a wider part of the hair.

Autoimmune diseases occur when the immune system becomes too active and mistakenly attacks the body’s own tissues. Typically, the immune system produces antibodies to protect our bodies from harmful things like viruses and toxins. However, in autoimmune disorders, it can’t tell the difference between harmful invaders and healthy cells. There are over 100 types of autoimmune diseases. The exact causes or triggers are not fully understood. Treatments generally aim to reduce the activity of the immune system.

Biotin is an important B vitamin for our health and is found naturally in some foods. It can also be taken as a supplement. Foods like organ meats, eggs, fish, meat, seeds, nuts, and certain vegetables, such as sweet potatoes, are rich in biotin. Biotin deficiency is rare, and it is highly unusual to see severe deficiency in healthy people who eat a normal diet. Symptoms of biotin deficiency usually appear slowly and may include thinning hair, which can eventually lead to losing all body hair.

The catagen phase begins when the anagen phase ends and usually lasts around ten days. During this time, hair follicles get smaller, and hair growth slows down. Even though the hair separates from the base of the follicle, it stays in place during its last days of growth. At any moment, about five percent of the hairs on our heads are in the catagen phase.

Scarring alopecia is a type of hair loss that happens when hair follicles are damaged. This damage is often caused by inflammation or autoimmune disorders but can also result from skin injuries, burns, or specific medical treatments. Once the hair follicle is destroyed, the hair cannot grow back, making the hair loss permanent.

Corticosteroids are medicines that have multiple effects on the body, allowing them to treat different health issues. They can lower inflammation, calm an overactive immune system, and help with hormone problems. These drugs work quickly, making them great for dealing with sudden and severe symptoms like allergies.

The crown refers to the area on the top of our heads. It includes the area behind the hairline, in the middle, between the head’s sides, and above the bump called the occipital bone. Crown thinning happens when someone notices their hair becoming thinner in this specific area.

Dandruff is a condition that primarily affects the scalp and causes flaking and sometimes mild itchiness. The exact cause of dandruff isn’t known, but it’s thought to be linked to both genetic and environmental factors, and it might get worse in the winter. Dandruff isn’t related to poor hygiene; instead, it involves the rapid growth of skin cells. Doctors diagnose it based on the symptoms.

A dermatologist is a doctor who focuses on identifying and treating skin problems. They are experts in understanding various skin conditions and helping people maintain healthy skin.

Diffuse thinning happens when hair all over the scalp starts to thin out or fall out. This is often due to a condition called telogen effluvium, which occurs when a large number of hair follicles on the scalp suddenly move into their resting phase.

Dihydrotestosterone, or DHT, is a natural hormone that plays a key role in the development and maintenance of the prostate and penis, as well as in producing skin oils and body hair. However, when DHT levels are too high, it can affect the hair by making the hair follicles smaller and shortening the time hair grows, leading to hair loss.

The exogen stage of hair loss is when hairs fall out as new ones grow. This happens when the anagen phase starts over. About 100 to 150 hairs normally fall out each day, but the exact number can differ for each person.

Finasteride is a medication often used for treating hair loss in men, known as androgenic alopecia, and for easing symptoms of an enlarged prostate. Finasteride works by blocking an enzyme that converts testosterone into a hormone called dihydrotestosterone (DHT). By reducing DHT, finasteride helps shrink the prostate, making urination easier and slowing hair loss in men. Finasteride is available under brand names like Propecia and Proscar.

A hair follicle is a tube-like structure in the skin’s outer layer, where hair begins to grow. The hair root, made of protein cells, gets nutrients from nearby blood vessels. As new cells form, the hair pushes through the skin and becomes visible.

Frontal fibrosing alopecia (FFA) causes hair loss at the front and sides of the scalp. It can also affect hair in other areas, like the eyebrows. FFA typically gets worse over time, but healthcare providers have treatments available to help slow its progression.

Genetic predisposition means having a higher likelihood of getting a specific disease because of your genes. This tendency, also known as genetic susceptibility, is often inherited from family members. However, it can also occur due to a sudden change in your genes.

Hair density refers to how many strands grow per square inch on the scalp. Hair density can be checked by looking at the scalp or feeling how thick a ponytail is.

Hair follicle miniaturization happens when the hair follicle becomes smaller, making it difficult for hair to grow. When this occurs, follicles that once produced strong, healthy hair begin to create thinner, weaker hairs that easily fall out. This process can lead to a receding hairline and balding. Miniaturization of hair can be caused by factors such as genetics, aging, and the hormone dihydrotestosterone (DHT), or a mix of all three.

There are various hair loss treatments available, including hair transplants, laser therapy, medications like minoxidil and finasteride, and natural supplements. To effectively treat hair loss, it’s important to first determine its cause.

Hair consists of two main parts: the hair shaft and the hair root. The shaft is the part that can be seen above the skin’s surface. Below the surface lies the hair root, which goes deeper into the skin. This root is encased in the hair follicle, a protective layer made up of skin and connective tissue.

A hair transplant is a medical procedure where a surgeon relocates hair to a bald spot on the head. Usually, the surgeon takes hair from the back or sides of the head and places it on the front or top. This process is done in a medical office using local anesthesia to numb the area.

Hormones are chemical messengers made by glands in the endocrine system and sent into the bloodstream. An imbalance happens when the levels of these hormones are too high or too low.

Iron deficiency anemia occurs when there’s not enough iron in the body, often due to blood loss or pregnancy. It’s typically treated with iron supplements and eating foods high in iron. If it becomes severe, iron deficiency anemia can lead to hair loss, including pattern hair loss known as androgenetic alopecia.

Keratin is a natural protein made by the body that provides structure and strength to our hair, skin, and nails.

Lichen planopilaris (LPP) is a condition that affects the scalp and hair. It is a type of lichen planus, which is an inflammatory disease that impacts the skin and mucous membranes. People with LPP might experience symptoms like scaly skin, redness around hair follicles, bald spots, and a painful, burning, or itchy feeling on the scalp. The exact cause of LPP isn’t fully known, but it seems that T-cells, which are part of the immune system, mistakenly attack the hair follicles. Because T-cells are involved, many experts think LPP might be an autoimmune disease.

Lupus, also called systemic lupus erythematosus, is an autoimmune disease where the immune system attacks healthy tissues by mistake. This can affect various parts of the body. When lupus affects the skin, it can damage the hair follicles on the scalp, leading to hair loss. This hair thinning might happen very slowly.

Pattern hair loss is a condition that mainly impacts the top and front parts of the scalp. For men, it usually appears as a receding hairline at the front, thinning hair on the crown, or both.

Minoxidil is a medicine used to treat high blood pressure and hair loss. It can help counteract hair loss due to androgenetic alopecia. It does this by reversing the shrinking of hair follicles, increasing blood flow around them, and encouraging them to enter the growth phase.

A nutritional deficiency occurs when there is a lack of essential nutrients, like vitamins and minerals, in a person’s diet. This can lead to malnutrition and other health problems. Some deficiencies, such as a biotin deficiency, might cause hair loss.

Alopecia areata is mainly identified by the loss of hair in small, round patches. These patches, about the size of a coin, typically appear on the scalp as hair begins to fall out.

Platelet-rich plasma (PRP) is a treatment created from a person’s own blood, used to boost healing and aid in the repair of certain injuries. PRP therapy is also used for treating hair loss, as it can help encourage and maintain hair growth.

Many new mothers experience hair loss about three months after giving birth, which might continue for up to six months. This is a normal part of the postpartum period and isn’t permanent. Most people’s hair returns to its usual thickness over time. The extra hair loss happens because estrogen levels drop after childbirth.

Psoriasis is a skin condition that creates itchy, scaly patches on the body and sometimes on the scalp. When it affects the scalp, it might cause hair loss if someone scratches or picks at the irritated spots. This hair loss is usually temporary.

Scalp ringworm, or tinea capitis, is a rash resulting from a fungal infection. It often leads to itchy, scaly, and bald spots on the head. This condition is mainly caused by fungi called Microsporum and Trichophyton. These fungi can enter the outer layer of hair follicles and may eventually invade the hair itself.

Minoxidil is a medicine that helps grow new hair, especially when hair loss runs in the family. You can use it as a liquid or foam on your scalp to encourage hair growth. This medication is also known by the brand name Rogaine.

Seasonal hair loss occurs when temperature changes affect the scalp and hair follicles, causing hair to fall out more quickly. The exact reason for this type of hair loss isn’t fully understood, but studies indicate it affects more women than men. It generally returns to normal levels over time, allowing hair growth to continue as usual.

Seborrheic dermatitis is a long-lasting skin condition that causes symptoms like flaky, scaly, greasy, and sometimes itchy and red skin. It often affects areas rich in oil-producing glands, such as the scalp, face, and chest. This condition is usually triggered by a combination of genetic and environmental factors. Seborrheic dermatitis is linked to hair loss because increased sebum production can irritate the scalp, leading to itchiness. Scratching can harm hair follicles, which disrupts natural hair growth and causes hair to fall out.

Telogen effluvium is when you lose hair quickly due to stress or changes in your body. Typically, your hair should start growing back within three to six months. While hair loss from stress is usually temporary, long-term stress can make hair shedding last longer and might even cause permanent damage by harming hair follicles.

The telogen phase of hair growth is when the hair takes a break from growing, and the hair follicle rests. At any given time, about 10% to 15% of our hair is in this phase. This phase usually lasts a few months.

Thyroid disease is a health issue that affects how the thyroid gland works. When the thyroid doesn’t function properly, it can lead to severe and long-lasting conditions like hypothyroidism or hyperthyroidism, which might cause hair loss. This hair loss affects the whole scalp, making the hair look thin all over rather than in patches. With successful treatment of the thyroid problem, hair often grows back, but it can take several months and may not completely return to normal.

A topical medication is a type of medicine used directly on a specific area of the body. It’s commonly applied to the skin or mucous membranes to address various health issues. These medications come in different forms, such as creams, foams, gels, lotions, and ointments, each designed to treat specific conditions.

Traction alopecia happens when hair is frequently pulled tight, leading to hair loss. This condition often affects women of African descent with tightly coiled hair. Hairstyles like braids, dreadlocks, or tight ponytails can cause the hair to be pulled too much, resulting in hair loss over time.

Trichology is the field of study and practice in both medicine and cosmetology that focuses on the health and care of hair and the scalp.

Trichorrhexis nodosa is a hair condition where parts of a hair strand become thick or weak, causing them to break easily. It can be inherited, meaning it runs in families. Activities like blow-drying, ironing, over-brushing, perming, or using too many chemicals can also trigger it. Sometimes, an underlying health issue might be the cause.

Trichoscopy is a technique used to examine hair and scalp conditions. It helps doctors diagnose various hair and scalp diseases by using a special tool similar to dermoscopy. This tool allows them to see the hair and scalp structures at a much higher magnification than the naked eye.

Vitamin D deficiency, also known as hypovitaminosis D, happens when the level of vitamin D in the body is lower than normal. This often occurs when people don’t get enough sunlight, especially UVB rays. When the body lacks vitamin D, it affects the keratinocytes, which are cells that help regulate the hair growth cycle. This can lead to slower hair growth and more hair shedding. With low vitamin D levels, the growth phase (anagen) of the hair cycle becomes shorter, while the resting phase (telogen) becomes longer.