What can an 18 year old girl do if she is experiencing hair loss?

Go see your doctor: Hair loss can occur for many reasons, thyroid disease, infection, vitamin deficiencies, and just plain old stress. You need a proper evaluation with your doctor which may include some blood work to get to the bottom of your hair loss issue.

Allopecia: Scalp hair loss in women may be due to hypothyroidism but this is rare if it is the only symptom. Thyroid disorders are usually autoimmune and so is allopecia-- aninflammation of the hair follicle. Autoimmune allopecia can be treated by local cortisone therapy -- see a dermatologist. If one has hirsutism and scalp hair loss you could have excess androgens. For that you can seean endocrinologist.