Managing Hidradenitis Suppurativa with Biologics and Small Molecule Inhibitors

April 3, 2025

This plain-language research summary was generated by AI, courtesy of HS Simplified.

AI Generated Content Verified By: Victoria Fang, M.D. Ph.D. | Penn Medicine

Managing Hidradenitis Suppurativa with Biologics and Small Molecule Inhibitors

In the battle against moderate to severe HS, biologics—large complex proteins like antibodies targeting specific immune pathways—and small molecule inhibitors—smaller, chemically synthesized drugs like Janus kinase (JAK) inhibitors—offer promising relief by tackling inflammation at its roots. As of 2025, FDA-approved therapies include adalimumab and secukinumab, achieving significant disease reduction in many patients. Bimekizumab was another biologic approved in 2025, after the publication of this article. However, effective management often requires personalized treatment strategies including medication adjustments and possible surgical interventions.

What is Hidradenitis Suppurativa (HS)?

Hidradenitis suppurativa (HS) is a long-lasting skin disease that causes swollen, painful bumps under the skin, especially in places like the armpits, groin, and buttocks. These bumps can break open and leak pus and bleed, sometimes leading to scars and tunnels under the skin. HS can make everyday life difficult and can also cause tiredness and increase the risk for other health problems like diabetes and heart disease.

HS is divided into stages, called Hurley Stages. Stage 2 and 3 are more severe, with more bumps, tunnels, and scars.

Why Do People Get HS?

Doctors and scientists aren’t totally sure why HS happens, but it seems to be caused by a mix of things: genes (things you inherit from your family), hormones, lifestyle, and even the types of bacteria living on your skin. The body’s immune system (your body's defense against germs) overreacts, causing swelling and blockages in hair follicles.

How is HS Treated?

There are many treatments for HS: creams, antibiotics, surgery, and stronger medicines called biologics and small molecule inhibitors.

• Biologics are special medicines made from living cells that target certain parts of the immune system. They are usually given as shots or infusions.

• Small molecule inhibitors are medicines made by mixing chemicals. They are usually taken as pills.

These medicines are usually used for people with moderate or severe HS (Hurley Stage 2 or 3), especially if other treatments haven't worked.

FDA-Approved Medicines for HS

So far, three biologics are approved by the FDA (Food and Drug Administration) for treating HS:

• Adalimumab (Humira): Blocks a protein called TNF, which causes inflammation. About half of patients see their HS improve by at least 50%.

• Secukinumab (Cosentyx): Blocks a protein called IL-17, which is also involved in swelling. It works almost as well as adalimumab for many people.

• Bimekizumab: Blocks IL-17A and F.

All are usually used along with other treatments, like creams, antibiotics, and sometimes surgery.

Other Medicines Sometimes Used for HS

Doctors sometimes try other biologics and small molecule inhibitors on a case by case basis. These include:

• Infliximab and golimumab: Similar to adalimumab, given by infusion.

• Ustekinumab: Blocks proteins IL-12 and IL-23.

• JAK inhibitors (like upadacitinib): Block certain signals in the immune system, taken as pills. These are in clinical trials now.

• Apremilast: A small molecule pill that helps lower inflammation.

These are not always officially approved for HS but have helped some patients in studies. Sometimes doctors need to try different medicines to find what works best.

How Do Doctors Measure Improvement?

Clinical trials check if a person’s HS is getting better using a score called HiSCR (Hidradenitis Suppurativa Clinical Response). Reaching "HiSCR50" means someone has 50% fewer swollen bumps and no new draining areas. About half of people on adalimumab, secukinumab, or bimekizumab reach this goal.

Are There Any Side Effects?

Biologics and small molecule drugs can cause side effects. Common ones include redness or pain where you get a shot, getting the common cold, and more rarely, infections. Because these medicines calm the immune system, they can make it a little easier to get sick. That’s why doctors do tests for things like tuberculosis or hepatitis before starting treatment.

Secukinumab and bimekizumab are not recommended if you have certain health conditions like inflammatory bowel disease (IBD). Adalimumab is not recommended if you have multiple sclerosis or heart failure. JAK inhibitors can rarely increase the risk of blood clots or heart problems, so doctors watch patients closely.

Other Treatments

If someone has a severe HS flare (sudden worsening), doctors might use steroids for a short time or strong antibiotics like ertapenem (given through a vein) to calm things down. Surgery to remove tunnels under the skin (called deroofing) can also help and is sometimes used with medicines.

What About Special Situations?

Pregnancy: Some biologics are safer than others during pregnancy. For example, adalimumab is often used during pregnancy, and certolizumab does not cross the placenta, so it is safer for the baby. Always, doctors and patients need to talk carefully about the best choice.

Children: Adalimumab is the main biologic used for kids with HS, but there aren’t many studies in children.

Limitations of Treatment

These medicines do not work for everyone. Even for the best options, about half of patients see big improvements, while others need to try different plans. Some medicines can be expensive or hard to get through insurance. Also, most studies are on adults, not kids, and many treatments are not officially approved for HS yet.

HS is a tough, long-term disease, and it usually takes a mix of medicines, surgery, and lifestyle changes to feel better. Doctors try to find the best plan for each person and may need to adjust the treatment over time.

Summary

HS is a painful skin problem that often needs strong medicines to control. Biologics and small molecule inhibitors have made a big difference for many people with moderate to severe HS. But there is no one-size-fits-all solution, and working with a dermatologist is important to find the right treatment for each person.

Author(s)

Victoria Fang, Radhika Gupta, Robert G Micheletti

Read Original Paper

https://www.sciencedirect.com/science/article/abs/pii/S0733863524001086?via%3Dihub