Alopecia Areata

Overview

Alopecia areata is an autoimmune disease where the immune system attacks hair follicles resulting in hair loss. Alopecia is a medical term for hair loss, while areata refers to the patchy nature of such hair loss. Most commonly patients present with one to several round patches of hair loss, however, in rare cases loss may be more significant and encompass the entire scalp (alopecia totalis) or all body hair (alopecia universalis). It can occur at any age and affects both men and women. There is no known cure, but there are treatments that can help hair regrow.

Symptoms

Symptoms of alopecia areata include patchy hair loss, which can occur on the scalp, face, or body. Hair may also become thinner all over the scalp. Most people with alopecia areata do not lose all of their hair, however, rarely patients can lose all of their scalp hair (alopecia totalis) or all of their body hair (alopecia universalis).

Image 1) Source: https://commons.wikimedia.org/wiki/File:Alopecia_areata_1.jpg License: Thirunavukkarasye-Raveendran, CC BY 4.0 <https://creativecommons.org/licenses/by/4.0>, via Wikimedia Commons

Image 2) Source: https://commons.wikimedia.org/wiki/File:Alopecia_areata_bald_spot.jpg License: Kevlaraz, CC0, via Wikimedia Commons

Image 3) Source: https://commons.wikimedia.org/wiki/File:Alopecia_areata_0001.jpg License: Carolyn P Speranza, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons

Causes

The cause of alopecia areata is unknown. It may be caused by a combination of genetic and environmental factors. Some possible triggers include stress, illness, or injury. One hypothesis is that following illness, the immune system is primed to recognize foreign antigens (such as bacteria or viruses). In genetically susceptible individuals in this primed state the immune system mistakenly targets hair follicles. When the body is under stress (whether emotional or physical) the immune system can also be more likely to target hair follicles.

Alopecia areata is also associated with other autoimmune diseases such as autoimmune thyroid disease, diabetes, and lupus.

Treatment

There is no known cure for alopecia areata, but there are treatments that can help hair regrow.

Options include:

- Steroid injections: These are typically given every four to eight weeks and can help promote hair growth by targeting immune cells in the scalp.

- Topical steroids: A steroid cream or ointment applied to the scalp can help hair regrow in some people. This is often preferred in pediatric patients as it is less traumatic but generally less effective than steroid injections.

- Systemic steroids: Oral prednisone or dexamethasone can suppress the immune system temporarily and can limit progression of alopecia areata when started promptly.

- Minoxidil: This is a topical solution that is thought to help hair regrow by increasing blood flow to the scalp. In severe cases of alopecia areata, it is also prescribed orally to help promote and maintain hair growth.

- Anthralin cream: This cream is applied to the scalp to induce irritation and thereby trick the immune system into "forgetting" hair follicles as targets.

- JAK inhibitors: Baracitinib (olumiant) is the first FDA approved medication to treat alopecia areata. Studies in patients with 80% or more hair loss at baseline show roughly 40% of patients get 90% or more regrowth at the higher dose.

 

Diagnosis

Alopecia areata is usually diagnosed based on a physical examination and dermoscopy/trichoscopy. A biopsy of the affected skin may be done to rule out other causes of hair loss, such as fungal infections or telogen effluvium.

 

Outlook/Prognosis

Most people with alopecia areata will experience hair regrowth at some point. For some, the hair loss is temporary and will resolve on its own. In others, the hair loss may be more persistent, but can be treated with medication. Rarely, alopecia areata can lead to scarring and irreversible hair loss.

Source: https://commons.wikimedia.org/wiki/File:Alopecia_areata.svg

License: Priscilla king, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

FAQs - Alopecia Areata

  • - Steroid injections: These are typically given every four to eight weeks and can help promote hair growth by targeting immune cells in the scalp.

    - Systemic steroids: Oral prednisone or dexamethasone can suppress the immune system temporarily and can limit progression of alopecia areata when started promptly.

    - Minoxidil: This is a topical solution that is thought to help hair regrow by increasing blood flow to the scalp. In severe cases of alopecia areata, it is also prescribed orally to help promote and maintain hair growth.

    - JAK inhibitors: Baracitinib (olumiant) is the first FDA approved medication to treat alopecia areata. Studies in patients with 80% or more hair loss at baseline show roughly 40% of patients get 90% or more regrowth at the higher dose.

  • Studies currently suggest that alopecia areata may be a dermatologic manifestation of COVID-19, with cases most often appearing 1 to 2 months following infection. However, the heterogeneity of study designs and a high proportion of case reports make it challenging to draw any conclusions, and further research is necessary to better elucidate the relationship between the clinical course of alopecia areata and COVID-19.