Hereditary or Female Pattern Baldness

• Hereditary or common baldness, also referred to as "female pattern alopecia," is genetic. It passes on from either the mother or father, and is caused by the enzymes aromatase and 5-a reductase, which are linked to production of the hormone dihydrotestosterone (DHT). DHT is responsible for the shrinkage of hair follicles. Women with hereditary baldness may not respond well to DHT-blocking medications for male pattern baldness, such as Propecia, because of the presence of the female hormone aromatase.
  
  

Telogen Effluvium

• This type of diffuse hair loss in women is related to underlying medical conditions or trauma. Common triggers are childbirth, menopause, thyroid disease, lupus, anemia, bulimia, malnutrition, lichen planus, infection, surgery or acute stress. Telogen effluvium usually begins within six weeks to three months of the illness or event. In most cases, it is reversible once the illness or trauma heals, but it can become a chronic condition with individual triggers.
  
  

Anagen Effluvium or Drug-Induced Hair Loss

• Chemotherapy is responsible for anagen effluvium in women, a diffuse type of hair loss. Chemotherapy attacks rapidly dividing cells in the body, including hair follicles in the growing phase. The extent of anagen effluvium hair loss varies, but it commonly causes complete baldness. Hair regrowth occurs once chemotherapy ends. Hair loss also is a side effect of several drugs, including some blood thinners, diuretics, anti-inflammatories, antidepressants and oral contraceptives, as well as medications for thyroid disease, hypercholesterolemia, seizures, gout and high blood pressure.
  
  

Localized Hair Loss

• Localized hair loss occurs due to facial surgeries, such as facelifts and wound repair. Traction or scarring alopecia is a specific type of localized hair loss caused by continual tugging on the hair follicles due to tight hair styles. Women with cornrows, braids, ponytails and hair extensions often suffer from traction alopecia. Trichtillomania is another type of localized hair loss caused by emotional, compulsive hair pulling. Prompt psychiatric treatment can help women with trichtillomania.
  
  

Triangular Alopecia

• Triangular alopecia occurs as early as childhood and presents itself as hair loss in the temple areas. The extent of hair loss in the temple areas varies, and it is treated with medication and surgical implants. The cause of triangular alopecia is unknown.
  
  

Alopecia Areata

• Alopecia areata is an autoimmune disorder that causes sudden onset of hair loss in round patches on normal skin. It is a genetic, non-scarring type of hair loss that is treated with steroid injections. Prompt diagnosis by a physician will help prevent further bald spots from appearing.