Printer icon



Alopecia is a general medical term used for all types of hair loss, both localized or diffuse, from the scalp or any part of the body. There are many things that can cause hair loss, including medications or iron deficiency. They are generally divided into two groups: scarring (also known as cicatricial) and non-scarring.

Scarring (cicatricial) alopecia

Scarring alopecias are typically caused by inflammation that results in destruction of the hair follicle leading to irreversible hair loss. If the condition is treated early in the disease course, it is sometimes possible to regrow hair. Causes of hair follicle destruction include fungal infection, chemicals such as hair relaxers, mechanical traction, and inflammatory disorders which include discoid lupus erythematosus, lichen planopilaris, dissecting cellulitis, tufted folliculitis, folliculitis decalvans, alopecia mucinosa, central centrifugal cicatricial alopecia, and acne keloidalis. There are many treatments for these varying conditions and are often specific to the particular condition.

More information and support can be obtained from the Cicatricial Alopecia Research Foundation.

Non-scarring alopecia

Non-scarring alopecias are more common than scarring alopecias and include male and female pattern hair loss (also known as androgenetic alopecia), alopecia areata, telogen effluvium, and trichotillomania as well as other less common conditions. Sometimes diseases such as secondary syphilis, thyroid disease, and systemic lupus erythematosus can lead to non-scarring hair loss also. Non-scarring hair thinning can also occur with natural aging, which is known as senescent alopecia.

Androgenetic alopecia

Androgenetic alopecia is the most common type of hair loss and is so common that many experts believe it should be considered a normal variant such as blue eyes or brown hair. It is inherited in a complex manner from either or both parents. Androgens are hormones including testosterone that are present in both males and females. They also play an important role in the development of pattern hair loss. Even though increased androgen activity leads to hair loss, the majority of males and females with pattern hair loss do not have abnormal levels of testosterone. For males, the pattern typically involves loss of the frontal hairline with or without hair loss at the vertex (or top of the scalp) and may or may not progress over time. For females, the pattern is more variable, but most often spares the frontal hairline and involves diffuse thinning of hair over the crown of the scalp, sparing the back. This again may or may not progress over time.

It is important to note that this pattern of hair loss can be caused by an abnormal increase of androgens due to polycystic ovarian disease or less commonly due to a malignancy. These causes are usually associated with other symptoms such as abnormal periods. Testosterone and other hormone levels can be checked to aid in the diagnosis of these conditions.

Treatment for androgenetic alopecia includes topical minoxidil solution or foam, finasteride pills by mouth, or hair transplant surgery.

Alopecia areata

Alopecia areata is a type of non-scarring hair loss that can affect men and women, adults and children. The hair is usually lost in round or oval patches initially. This lost hair usually grows back without any other problems or any further hair loss. Less often, the patches can grow larger and hair loss can include the entire scalp or even the entire body. In these forms of alopecia areata, the hair is not as likely to grow back. It is thought to be an autoimmune disease in which the affected hair follicles are mistakenly attacked by a person's own immune system. About 20% of those with alopecia areata also have a relative with alopecia areata. Sometimes, nail changes can also occur in this condition.

Although hair can often grow back on its own in alopecia areata, there are treatments that may be helpful. Still, there is no cure for alopecia areata. Topical steroids, corticosteroid injections into the skin are typically used first. Many other topical treatments can be used. For more extensive disease, sometimes medication by mouth can be prescribed. These act by suppressing the immune system, but also are not always effective.

More information and support for individuals with alopecia areata is available from the National Alopecia Areata Foundation at

Telogen effluvium

Telogen effluvium is a common, transient form of hair loss that can be due to medication, pregnancy, hypothyroidism, or some type of physical or psychological stressor such as surgery or a severe illness. In the normal scalp, hairs are on varying cycles of resting (telogen) and growing (anagen) phases. With one of the above or other stresses to a person, it is possible for a significant number of hairs to convert to the resting phase. This usually is seen about 3-6 months after the stressor. Some medications that commonly cause telogen effluvium are anti-seizure medications, beta-blockers for high blood pressure, and anti-thyroid medications. In this situation, these medications should only be stopped after discussion with your doctor. There is no particular treatment for this as hair re-growth almost always occurs.

Many chemotherapy drugs are expected to cause hair loss. Growing hairs in anagen phase are affected in this case. This type of hair loss is reversible.


Trichotillomania is self-induced plucking or breakage of hair that is often done subconsciously. It often occurs in children or adolescents. In young children, this is often more like a habit that will eventually resolve on its own, but in adolescents, psychiatric treatment may be indicated.

For more information, please visit the following websites: