Alopecia areata is the loss of hair in patches that can proceed to loss of all hair (alopecia totalis or universalis). The purpose of the registry is to collect patient information and blood samples from people with alopecia areata. Alopecia areata is a condition in which hair is lost either from part of the scalp, all of the scalp, or the entire body, and it affects 1% to 2% of the population. It is thought to be an autoimmune disease and in some cases the disease is hereditary. The Alopecia Areata Registry will collect information and blood samples from clinically well-characterized patients with these three forms of alopecia areata: alopecia partialis (patchy loss of the scalp hair), alopecia totalis (total loss of all scalp hair), and alopecia universalis (complete loss of all hair everywhere on the body). This will be a collection of patients in multi-generational families, twins, single patients with patchy, persistent transient alopecia areata or long-standing alopecia totalis/universalis and with controls (persons unaffected and not related to alopecia patients). Information from these patients will be used to search the human genome for disease-associated loci and/or genes. Researchers interested in doing pathophysiology or treatment studies of this disease will also be able to contact patients having the appropriate form of the disease for the studies in question. Patients who have been diagnosed with alopecia areata by a dermatologist will be eligible for the registry. Patients will fill out an information form online (alopeciaareataregistry.org). Patients who have a family history or specific types of alopecia will be invited to participate in a more detailed questionnaire and physical exam and have blood samples drawn.