There are many other causes of hair loss besides androgenetic alopecia or male pattern baldness. Sometimes hair loss is associated with serious diseases. In general, when a serious illness is the cause, hair loss is not the only symptom of the disease. In these cases, it is important for the primary disease that is causing the hair loss to be treated. Some causes of hair loss include:
- Nutrient deficiencies and excess: Iron deficiency anemia, deficiencies of certain B vitamins protein deficiency, and zinc deficiency can all cause hair loss. Too much vitamin A can also cause hair loss.
- Chronic illness: Various chronic illness can affect hair growth and contribute to hair loss. Some examples include thyroid disorders, uncontrolled diabetes, anorexia nervosa, cancer, and cancer treatment, and many others.
- Autoimmune diseases: Some autoimmune diseases are known to cause hair loss. Some examples include lupus and alopecia areata.
- Scarring from injuries or inflammation: Examples includes burns and other types of damage to the skin or scalp.
- Infections of the scalp: Examples include tinea capitis and kerion, both examples of fungal scalp infections.
- Hormones: Women with polycystic ovarian syndrome (PCOS) and men who take anabolic steroids may lose hair as a result of excess androgens (testosterone-like hormones).
- Medications: Many medications can cause hair loss, including blood thinners, gout medications, beta blockers, NSAIDs, ACE inhibitors, some acne medications, some antidepressants, and some seizure medications.
Stress: Stress alone can cause hair loss, but it is often an additional factor when other causes are at work. Some conditions result from stress alone and can resolve when the stress resolves with complete restoration of hair. Alopecia areata is a predominantly autoimmune process but it has long been known that stressful events, anxiety and even depression precede some cases. It is also known that stressful life events (e.g., death of a loved one, illness, or divorce) can lead to hair loss, resolving completely when the stress is relieved. Lastly, an inability to control the urge to pull repeatedly on hair can lead to hair loss. This is an impulse control disorder called trichotillomania.