Hair loss

Hair loss
Other names	Alopecia, baldness
A bald spot on a man
Pronunciation	Alopecia: /ˌæləˈpiːʃ(i)ə, -si.ə/[1]
Specialty	Dermatology
Symptoms	Loss of hair from part of the head or body.[2]
Complications	Psychological distress[3]
Types	Male-pattern hair loss, female-pattern hair loss, alopecia areata, telogen effluvium[4]
Treatment	Accepting the condition, medications, shaving of balding areas, surgery[4]
Medication	Pattern hair loss: minoxidil, finasteride[5] Alopecia areata: steroid injections[4]
Frequency	50% of males, 25% of females (pattern hair loss by age 50)[4][6]

Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body.^[2] Typically at least the head is involved.^[4] The severity of hair loss can vary from a small area to the entire body.^[7] Inflammation or scarring is not usually present.^[4] Hair loss in some people causes psychological distress.^[3]

Common types include male- or female-pattern hair loss, alopecia areata, and a thinning of hair known as telogen effluvium.^[4] The cause of male-pattern hair loss is a combination of genetics and male hormones; the cause of female pattern hair loss is unclear; the cause of alopecia areata is autoimmune; and the cause of telogen effluvium is typically a physically or psychologically stressful event.^[4] Telogen effluvium is very common following pregnancy.^[4]

Less common causes of hair loss without inflammation or scarring include the pulling out of hair, certain medications including chemotherapy, HIV/AIDS, hypothyroidism, and malnutrition including iron deficiency.^[3][4] Causes of hair loss that occurs with scarring or inflammation include fungal infection, lupus erythematosus, radiation therapy, and sarcoidosis.^[3][4] Diagnosis of hair loss is partly based on the areas affected.^[4]

Treatment of pattern hair loss may simply involve accepting the condition, which can also include shaving one's head.^[4] Interventions that can be tried include the medications minoxidil (or finasteride) and hair transplant surgery.^[5][6] Alopecia areata may be treated by steroid injections in the affected area, but these need to be frequently repeated to be effective.^[4] Hair loss is a common problem.^[4] Pattern hair loss by age 50 affects about half of men and a quarter of women.^[4] About 2% of people develop alopecia areata at some point in time.^[4]