• Biologics are a category of medications that treat hidradenitis suppurativa (HS) by targeting specific proteins involved in inflammation.
• There are several studies and clinical trials underway studying new and existing biologics for the treatment of HS.

Many classes of drugs have been developed to help manage and treat hidradenitis suppurativa (HS), including antibiotics, topicals, retinoids, and more. These treatment options are prescribed to manage the lesions, bumps, and scarring on the skin that HS can cause.

Biologic drugs are used to treat severe HS by dampening the immune system, helping to control inflammation. Biologics are made of proteins, sugars, or nucleic acids. Unlike other drugs that are chemically synthesized, biologics are derived from living organisms. Examples of biologics include vaccines, gene therapy, and monoclonal antibodies used to treat cancer and arthritis.

What Is Hidradenitis Suppurativa?

HS, also known as acne inversa, is an inflammatory skin disease that causes small, painful bumps to form under the skin. These form in areas with friction where the skin rubs against itself, such as the groin, armpits, breasts, and buttocks. This can cause the formation of lumps, abscesses, sinus tracts, and scarring.

HS is thought to be caused by blocked hair follicles, in addition to chronic inflammation. However, the exact cause of the condition is unknown. Many people with HS have increased levels of inflammatory markers known as cytokines, which can be managed using biologic treatment.

HS is also known to occur alongside other diseases, known as immune-mediated inflammatory diseases. These can include Crohn’s disease, ulcerative colitis, pyoderma gangrenosum, and seronegative arthritis.

How Do Biologics Work?

To understand how biologics are used to treat HS, it is important to know a little more about the immune system, inflammation, and a class of biologics known as monoclonal antibodies.

Antibodies are proteins that form a vital part of the immune system. They are produced by specialized immune cells, known as B cells, to fight bacterial or viral infections. The human body is capable of making almost 100 billion different types of B cells, and each type of B cell produces only one type of antibody. Each antibody is a protein that recognizes and interacts with a very specific target.

B cells can also be genetically altered in a lab to produce specific antibodies that will attach to a target protein. These are known as monoclonal antibodies because they are produced from one type of B cell.

Every antibody made by that B cell will have the same properties. Researchers have designed monoclonal antibodies to target specific proteins on the outside of immune cells, cancer cells, and other abnormal cells associated with the disease.

Biologics for Hidradenitis Suppurativa

There are several categories of biologics with different targets. Humira (adalimumab) was the first biologic approved by the FDA to treat HS. Humira works by binding to tumor necrosis factor-alpha (TNF-alpha), which is involved in inflammation. In HS, TNF-alpha can cause inflammation that leads to inflammatory nodules, abscesses, and draining fistulas. Cosentyx (secukinumab) was approved in 2023 by the FDA to treat HS.

Two other biologics — Stelara (ustekinumab) and Remicade (infliximab) — have not been approved by the FDA for use in HS. However, doctors may prescribe them off-label to treat cases that have not responded well to other treatments. Stelara works by blocking inflammation caused by the cytokines interleukin-12 (IL-12) and IL-23. Remicade is also a TNF-alpha blocker and binds directly to the protein to dampen inflammation.

When Is The Right Time To Consider Biologic Treatment?

Biologics are typically used to treat moderate to severe HS or in cases where other treatments have failed to work. Your dermatologist will discuss your treatment options and evaluate which may work best for you. Biologics may also be a good option if you are being treated for another inflammatory disease.

What To Expect When Starting Biologics

All biologics are given as injections or infusions — either subcutaneous (under the skin), intramuscular (into muscle), or as intravenous infusions. Biologics cannot be taken by mouth because they would be broken down in the stomach and intestines before being absorbed into the bloodstream.

Before you start biologic therapy, you may undergo screening tests to make sure you are not at risk from any underlying conditions. Screening may include tests for tuberculosis and hepatitis B and C. You may be monitored regularly for these or other conditions during treatment with biologics to make sure you are not at risk for developing any complications.

Side Effects of Biologics

In most cases, the benefits of using approved drugs to treat a condition outweigh the possible side effects you may experience. The overall goal of treatment is to improve your quality of life. If you notice side effects, talk to your doctor about how to manage them and ask whether they may fade over time.

Common side effects associated with biologic drugs include:

• Headaches
• Redness, pain, swelling, and itching at the injection site
• Nausea
• Increased risk for infections because the drugs work by suppressing the immune system
• Injection or infusion reactions, which are similar to allergic reactions (rash, pain, swelling, flushing, headache, etc.)

Always listen to your body. If you experience any of these new symptoms after using biologic drugs, contact your doctor right away:

• Painful rash or sores
• Fever, sweat, or chills
• Chest pain
• Dizziness
• Shortness of breath
• Cough
• Bleeding or bruising easily
• Vision problems
• Diarrhea or stomach pain

These are all signs of an infection or a more serious condition that should be addressed immediately.

What Is Being Researched?

Several clinical trials are investigating new or available biologics for treating HS. These trials are promising for the development of new treatments, or the repurposing of already-existing drugs.

New biologics being studied to treat moderate to severe HS include:

• Bimekizumab — Inhibits the function of IL-17A and IL-17F
• Brodalumab — Inhibits the function of IL-17 receptor A (IL-17RA)
• Spesolimab — Inhibits IL-36 receptor (IL-36R) and is currently being studied for the treatment of Crohn’s disease, psoriasis, and other autoimmune diseases

Talk With Others Who Understand

On myHSteam, the social network for people with hidradenitis suppurativa and their loved ones, more than 21,000 members come together to ask questions, give advice, and share their stories with others who understand.

Have you tried treating your HS with biologics? Share your experience in the comments below, or start a conversation by posting on myHSteam.