Hair loss: types, causes and treatment options

Alopecia is the medical name for hair loss. Losing some hair every day is normal: the American Academy of Dermatology puts it at about 50 to 100 hairs a day, and MedlinePlus at 50 to 200. It is not normal to shed much more than that for weeks, to see your part widening or your scalp showing through, or to find bald patches.

Hair loss can be temporary (hair grows back once the cause passes) or progressive (like hereditary balding, which keeps advancing without treatment). Knowing which type you have saves you money on products that will not help.

Depending on the type, you may notice:

• More hair than usual on your pillow, brush or in the shower
• A wider part or thinner hair at the crown
• A receding hairline at the temples
• Round, smooth bald patches on the scalp, beard or eyebrows
• An itchy, scaly or red scalp

Androgenetic alopecia (male and female pattern hair loss). The most common cause. MedlinePlus notes that about 80% of men show signs of male pattern baldness at some point: the hairline recedes and the crown thins. In female pattern hair loss, hair thins mostly along the part and the top of the head, while the front hairline stays.

Telogen effluvium. Heavy, diffuse shedding that starts a few months after a physical or emotional stress: childbirth, a high fever or infection (such as dengue or COVID-19), surgery, major weight loss, a divorce or stopping birth control pills. The American Academy of Dermatology says hair usually regains its fullness in about 6 to 9 months once the trigger passes.

Alopecia areata. The immune system attacks hair follicles, causing round, smooth bald patches, sometimes in the beard or eyebrows too. It has its own section below.

Traction alopecia. Caused by hairstyles that pull for a long time: tight braids, buns, ponytails and extensions. Caught early, loosening the style helps hair return.

Scalp ringworm (tinea capitis). A fungal infection, most common in children, that causes scaly patches with broken hairs. MedlinePlus explains it is treated with an antifungal taken by mouth plus a shampoo, because creams do not reach the hair root. See also fungal skin infections.

Often your history and what the doctor sees on camera are enough to tell the type. When the doctor suspects a health cause, she gives you a lab order for a lab near you and reviews the results with you. Depending on your evaluation, she may order:

• TSH for your thyroid: both hypothyroidism and an overactive thyroid can cause hair loss
• A blood count and ferritin, to look for anemia or low iron stores
• Vitamin D or vitamin B12, when your symptoms or history point that way
• Hormone tests, if you have irregular periods, acne or facial hair, which can point to polycystic ovary syndrome (PCOS)

The American Academy of Dermatology advises taking supplements only when a test confirms a deficiency. If the doctor thinks a medicine you already take may be behind the shedding, she reviews it with you before any change.

Treatment depends on the type. For telogen effluvium, the focus is treating the cause and waiting: hair grows back on its own. For pattern hair loss, there are treatments that slow shedding and help restore density:

• Topical minoxidil. Sold over the counter as a 2% or 5% solution or a 5% foam, for men and women. It has to be used continuously, and results take months.
• Finasteride. A daily pill FDA-approved for male pattern hair loss, in men only.
• Spironolactone. Used off-label for female pattern hair loss. The American Academy of Dermatology says it helps about 40% of women and must not be used during pregnancy.

If appropriate, the doctor prescribes and we send your prescription to your pharmacy. Read how each one works, how long it takes and its side effects in the minoxidil and finasteride guide.

Be consistent and give treatment time: most take 3 to 6 months to show, and results last only as long as you keep using them.

Alopecia areata is an autoimmune condition: the body's defenses attack the follicles and hair falls out in round, smooth patches. It can start at any age. In many people hair grows back on its own, but it can come back.

For a few patches, the most common treatment is corticosteroid injections into the area, given in person every 4 to 8 weeks. In 2022, the FDA approved the first oral treatment for severe alopecia areata in adults, a JAK inhibitor. These medicines need tests before starting and close follow-up.

The doctor evaluates you by video, checks for related autoimmune conditions (such as thyroid disease) with a lab order and, when alopecia areata needs injections or a JAK inhibitor, we refer you to a dermatologist.

Dandruff, itching and greasy scales on the scalp are usually seborrheic dermatitis, which is controlled with medicated shampoos. It does not usually cause baldness, but heavy scratching can break hairs. If you have dandruff and are also losing hair, the doctor looks at both in the same visit.

You see Dr. Diana Nieves Castro, a Puerto Rico–licensed general practice physician with several years of emergency-department experience, in English or Spanish. Video doctor visits 24/7: book online and choose your time right away.

Use good light so the doctor can see your scalp on camera; if she asks, you can send photos through the secure link. We evaluate, diagnose and treat; if needed, we give you a lab order for a lab near you. If a treatment already works for you, you can request a refill in a follow-up visit. See also online skin care.

We see children of all ages; a parent or legal guardian is on camera with ID. In children, scaly patches are often scalp ringworm, which needs treatment by mouth; alopecia areata and hair loss from tight hairstyles also happen. The doctor evaluates your child by video and tells you if an in-person visit is needed.

Hair loss is rarely an emergency, but for your safety get in-person care if you notice:

• Smooth, shiny or scarred areas of scalp where hair no longer grows
• Sudden patchy hair loss with scalp pain, burning or tenderness
• A soft, swollen, pus-filled lump on a child's scalp, especially with fever
• Hair loss with unexplained weight loss, fever or severe fatigue