What causes sudden hair loss in one spot?

Author: Cary Lockman  |  Last update: Sunday, August 3, 2025

Alopecia areata is a disease that happens when the immune system attacks hair follicles and causes hair loss. Hair follicles are the structures in skin that form hair. While hair can be lost from any part of the body, alopecia areata usually affects the head and face.

Why do I have a random bald spot all of a sudden?

Hair loss (alopecia) can affect just your scalp or your entire body, and it can be temporary or permanent. It can be the result of heredity, hormonal changes, medical conditions or a normal part of aging. Anyone can lose hair on their head, but it's more common in men.

Why is my hair falling out in one spot?

Alopecia areata is an autoimmune disease that causes patchy hair loss anywhere on your body, but it most commonly affects the hair on the skin that covers your head (scalp). “Alopecia” is a medical term for hair loss or baldness, and “areata” means that it occurs in small, random areas.

What does sudden hair loss indicate?

Symptom of a medical illness — Hair loss can be one of the symptoms of a medical illness, such as systemic lupus erythematosus (lupus), syphilis, a thyroid disorder (such as hypothyroidism or hyperthyroidism), a sex-hormone imbalance or a serious nutritional problem, especially a deficiency of protein, iron, zinc or ...

Should I worry about a bald spot on my head?

When to call a professional. Make an appointment to see your doctor if: you suddenly develop a bald spot on your scalp. your hair stylist tells you that your hair is thinning, or that you have small bald areas.

Doctor explains Alopecia Areata (aka patchy or total hair loss) - Signs, Symptoms, Treatment & more

Can hair grow back in a bald spot?

In most people, new hair eventually grows back in the affected areas, although this process can take months. Approximately 50 percent of people with mild alopecia areata recover within a year; however, most people will experience more than one episode during their lifetime.

What does hair loss from stress look like?

No Visible Pattern. With stress-related shedding, hair falls out evenly all over your scalp instead of in a defined pattern. You'll likely notice more hairs than usual coming out while shampooing, combing, or on your pillow, clothing, and bathroom floor.

What kind of illnesses lead to hair falling out rapidly?

Alopecia areata: Alopecia areata is an autoimmune disease that results in hair loss from the head and body. Telogen effluvium: This type of hair loss involves rapid shedding of hair in a short amount of time.

What does thyroid hair loss look like?

Severe and prolonged hypothyroidism and hyperthyroidism can cause loss of hair. The loss is diffuse and involves the entire scalp rather than discrete areas. The hair appears uniformly sparse.

What deficiency causes sudden hair loss?

Only riboflavin, biotin, folate, and vitamin B12 deficiencies have been associated with hair loss. Vitamin B2 (riboflavin) is a component of two important coenzymes: flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) [22].

Why is my hair thinning on one part of my head?

Common causes: trichotillomania, age-related hair loss, scalp conditions, trauma, alopecia areata, telogen effluvium, scarring alopecia, and traction alopecia.

Should hair come out when running fingers through it?

It's perfectly normal to lose a few stray strands when running your fingers, or a comb, through your hair. But if you notice increased hair being pulled out when you are being gentle, this can be a cause of concern that you should get checked over.

Which autoimmune disease causes hair loss?

Alopecia areata is a disease that happens when the immune system attacks hair follicles and causes hair loss. Hair follicles are the structures in skin that form hair. While hair can be lost from any part of the body, alopecia areata usually affects the head and face.

Can stress cause a sudden bald spot?

Yes, stress and hair loss can be related. Three types of hair loss can be associated with high stress levels: Telogen effluvium. In telogen effluvium (TEL-o-jun uh-FLOO-vee-um), significant stress pushes large numbers of hair follicles into a resting phase.

How do I know if I'm losing too much hair?

It may be a sign that you're losing too much hair if: Increased shedding. Thinning or bald spots. Changes in hairline.

What is Hashimoto's hair loss?

In Hashimoto's disease this hair loss most commonly presents in the form of diffuse hair loss across the scalp and eyebrows. Additionally, the reduced functionality of the T3 and T4 hormone reduces overall sebum production, which can give a thin, brittle appearance to your hair.

What are signs that your thyroid is out of whack?

Symptoms
  • Tiredness.
  • More sensitivity to cold.
  • Constipation.
  • Dry skin.
  • Weight gain.
  • Puffy face.
  • Hoarse voice.
  • Coarse hair and skin.

Can low iron cause hair loss?

Low iron levels can lead to hair loss. Iron deficiency can trigger a condition called telogen effluvium, which increases hair shedding and limits hair growth. Iron deficiency hair loss can be reversed if you get your iron levels back to normal. Oral iron supplements can help replenish your body's iron stores.

Why is my hair falling out like crazy all of a sudden?

Among the common causes are high fevers, childbirth, severe infections, severe chronic illness, severe psychological stress, major surgery or illnesses, over or under active thyroid gland, crash diets with inadequate protein, and a variety of medications.

What is the best shampoo for hair loss?

Top shampoos for thinning hair, at a glance
  • Best Overall: Nizoral Anti-Dandruff Shampoo, $15.
  • Best for Thickening: Kérastase Densifique Thickening Shampoo, $44.
  • Best for Damaged Hair: Vegamour Hydr-8 Shampoo, $38.
  • Best for Volume: Bumble and Bumble Thickening Volume Shampoo, $37.

What cancers cause hair loss?

Some types of cancer that can cause hair loss include:
  • Breast cancer.
  • Ovarian cancer.
  • Lung cancer.
  • Hodgkin's lymphoma.
  • Non-Hodgkin's lymphoma.

Can hair grow back after thinning?

You might be able to reverse hair loss, or at least slow it. With some conditions, such as patchy hair loss (alopecia areata), hair may regrow without treatment within a year. Treatments for hair loss include medications and surgery.

How do I know if my hair loss is hormonal?

Unlike hair loss caused by chemotherapy or autoimmune disorders, hormonal hair loss is gradual. You might not notice it until your hairline has visibly receded, your ponytail has grown thinner, or your scalp has become visible.

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