Causes of Circular Patchy Hair Loss in Women

By Jill Stansbury

  • Overview

    Alopecia is the medical term for hair loss. Alopecia areata is the term for the loss of hair from a small area on the scalp. The hair loss is often circular in appearance and can be due to drug side affects, infections, skin diseases or metabolic disorders. Most often a cause can be identified by a thorough review of the person's entire health and medical history.
  • Metabolic Disorders

    Metabolic disorders, particularly hypothyroidism can lead to hair loss. Hypothyroidism is often accompanied by dry itchy skin, increased tendency to rashes, poor healing wounds and dry frizzy hair. Hair loss may also occur as an extension of poor hair growth and poor scalp health. Blood tests can help identify insufficiency of thyroid hormones and other hormonal and metabolic disorders
  • Infections and Injuries

    Any severe infection in the body can lead to hair loss. Though hair loss due to infections is usually diffuse and not in a single patchy spot, hair loss may be more pronounced in certain spots about the head. Tuberculosis and syphilis are associated with hair loss, and any infection involving a sustained high fever can lead to hair loss. Any obvious injury to the scalp, such as burns and trauma, can result in permanent loss of hair follicles.

  • Skin Infections

    Skin diseases such as psoriasis of the scalp can also cause hair loss in one small spot. Fungal infections can cause lesions that are often circular in appearance and when on the scalp, a circular patch of hair loss. A dermatologist can often diagnose such scalp lesions by simply looking at them, but if there is any doubt, a gentle scraping of the scalp for examination under a microscope may display fungal elements or other diagnostic clues.
  • Systemic Diseases and Malnutrition

    Systemic diseases such as cutaneous lupus or auto-immune phenomena may be the underlying cause of hair loss. Severe protein malnutrition, somewhat rare in developed countries, and other nutritional deficiencies can cause hair loss.
  • Trichotillomania

    Another possible cause of alopecia areata is trichotillomania. Trichotillomania is a phenomenon where manual pulling of strands of hair from the same spot on the scalp becomes a nervous habit, and one which is often unconscious to the person doing the pulling. The evidence that trichotillomania is occurring, rather than other causes alopecia, is that the pulled hair grows quickly back. As there is not actual scalp, metabolic or other disease, the pulled hair grows back so that in the bald spot are many newly emerging hairs that are absent when hair growth is truly impaired.
  • Medication

    If you are on any medications, make sure hair loss is not a side affect. Toxic alopecia is the term for hair loss due to a drug or toxic substance. Heavy metal toxicity or any environmental toxin should be ruled out. An overdose of vitamin A can also lead to hair loss.
  • Considerations

    Sometimes no obvious underlying cause for alopecia can be found and the condition may display a lifelong course of clearing up and recurring again. Many such cases are presumed to be autoimmune phenomena that affects the hair follicles. When an obvious cause can not be identified, biopsies at the border of the alopecia may sometimes aid in diagnosis. Infectious elements, inflammatory and autoimmune process may become evident to an experienced histologist. Hormonal influences also produce characteristic effects on the hair follicle and microscopic evidence of such changes may help guide appropriate treatment.
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