Hidradenitis suppurativa (HS) is a chronic inflammatory condition affecting hair follicles. Alopecia areata is a type of autoimmune disorder where the immune system attacks otherwise healthy hair follicles, causing hair loss.

This article explains each condition and how they connect.

HS is a chronic inflammatory condition where painful, deep lumps form under the skin. Research suggests that HS involves hair follicle abnormalities with a connection to both inflammatory and autoimmune diseases.

According to the American Academy of Dermatology Association (AADA), people and doctors often mistake HS for acne cysts, infected hair follicles, boils, or a sexually transmitted infection. Misdiagnosis can lead to people living with the condition undiagnosed for years.

HS is a progressive disease and typically follows a similar progression:

  1. A person’s skin feels uncomfortable.
  2. Deep and tender nodules appear where the skin was tender.
  3. Nodules get larger and start to grow together.
  4. Painful and large abscesses form and begin to break open on the skin.
  5. In later stages, small blackhead-like spots appear, often appearing in pairs.
  6. Abscesses heal slowly, if at all.

In addition, a person may develop several complications related to living with HS. These can include:

  • an increased risk of skin infections
  • anxiety
  • depression
  • pain
  • itchiness
  • an increased risk of squamous cell carcinoma, a type of skin cancer
  • the development of deep tunnels under the skin

“Alopecia” means hair loss. Alopecia areata is an autoimmune disorder where the body’s immune system attacks hair follicles, leading to baldness. According to the AADA, there are three types of alopecia areata, including:

  • Alopecia areata: This type of alopecia can cause patchy hair loss anywhere hair grows on the body, including the face, eyelashes, scalp, armpits, or other areas.
  • Alopecia universalis: This is the rarest form and causes all hair on the body to fall out.
  • Alopecia totalis: This causes total hair loss on the scalp.

The condition often starts when a person is a child. People living with the condition often experience a regrowth of their hair after 12 months. They may never lose the hair again, or they may enter into a cycle where they periodically lose the same area or different areas of hair throughout their lives.

Typically, the only symptom of alopecia areata is hair loss that can worsen over time. The following are signs a person is living with alopecia areata instead of other forms of hair loss:

  • hair loss occurs in colder months
  • hair begins to regrow in the same spot it fell out
  • a new bald spot starts as another one goes away
  • white or gray hairs occur in areas of balding

Though research is somewhat limited, HS and alopecia areata appear to share some connections.

Autoimmune disease

In a 2019 study, researchers noted that alopecia areata is an autoimmune disorder. In the same study, researchers noted that HS is often associated with autoimmune diseases. They found that people living with alopecia areata had an increased risk of developing HS.

In a review of studies published in 2020, researchers noted that several autoimmune conditions often occur along with HS, including alopecia areata.

Vitamin D deficiency

According to a review of studies from 2019, some people living with alopecia areata and HS also have a vitamin D deficiency. However, as the AADA points out, additional studies are required because not all people living with alopecia also have an autoimmune disorder.

Additionally, the authors noted the researchers used only a very small number of people in the study, and not all people living with HS had a vitamin D deficiency.

Other similarities

The two conditions also share some similarities. Common characteristics of both conditions include:

  • Effects on hair follicles: Alopecia causes hair loss, while HS affects the hair follicles.
  • Psychological effects: Both conditions can cause a person to develop depression and anxiety.
  • Hereditary risk factors: A person who has a close family relative with either condition has a greater risk of developing it.
  • Some similar treatment options: These include corticosteroid injections.

A person should talk with their doctor about the best treatment options. The two conditions require different treatment approaches.

A person living with HS will need to develop a treatment plan with their doctor. Though every plan will be different, some common treatments for HS include:

  • a biologic, such as adalimumab (Humira), to help reduce the number of abscesses and nodules a person experiences
  • other medications to reduce symptom severity, such as acitretin, antibiotic pills, isotretinoin, resorcinol, metformin, or hormonal medications
  • pain medications
  • in-office procedures such as drainage, laser surgery, corticosteroid injections, deroofing, or laser hair reduction

A person living with alopecia areata may not require any treatment. In some cases, the condition will clear up on its own within 12 months. When a doctor determines that treatment is necessary, they may recommend one or more of the following:

  • corticosteroid injections
  • minoxidil (Rogaine), a topical ointment often used for male pattern baldness
  • anthralin, a topical ointment that can cause irritation and requires wiping off, which people typically use along with minoxidil
  • creams with corticosteroids
  • the use of wigs, extensions, and false eyebrows or lashes
  • JAK inhibitors, a newer therapy that researchers are still looking into
  • oral corticosteroids
  • methotrexate
  • topical immunotherapy, which changes how the immune system responds to the hair follicle

For both conditions, a doctor may ask the person how are they doing emotionally. Treatment plans often include a need to focus on mental health, such as treatments for depression or anxiety. Treatment for the related mental health conditions may include medications, counseling, or support groups.

Alopecia areata is an autoimmune disorder, and HS is a chronic inflammatory disease associated with several autoimmune disorders. A person living with either condition has a higher risk of developing the other. Both may also be associated with a vitamin D deficiency, though more research is needed to explore this connection.

A person should work with their healthcare team to determine the best treatment that fits their needs.