Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition. It involves painful breakouts of pimple-like bumps, nodules, and boils. These outbreaks often occur in areas where skin rubs together, such as the armpits and groin.

Experts do not know exactly what causes HS. An abnormal immune response may play a role. People with HS are more likely than others to have other inflammatory conditions, such as inflammatory bowel disease.

To manage HS, doctors may recommend lifestyle changes, surgical treatments, and medications. In some cases, they may prescribe a type of medication known as a biologic.

“We know from recent studies that biologics are more effective in earlier and less severe disease, so there is a trend to treat [early] to prevent progression to severe scarring disease,” Dr. John W. Frew, a researcher at the Laboratory of Investigative Dermatology at the Rockefeller University in New York, NY, told Medical News Today.

“The decision to start a biologic medication is an individual decision between a patient and their physician,” he continued.

Together, a doctor and a patient may consider many factors when deciding whether or not to add a biologic to the treatment plan. For example, they may consider:

  • how the condition is affecting the patient
  • how the condition has responded to other treatments
  • whether or not the patient has other health conditions
  • how they weigh the potential benefits of treatment against the risks

Read on to learn more about the role that biologics may play in treating HS.

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In some instances, a doctor may prescribe a biologic to treat HS.

Some experts believe that HS develops when the immune system has an abnormal inflammatory response to bacteria on the skin. Inflammation is one of the defenses that the immune system mounts against perceived threats.

According to one review, HS-related skin lesions contain elevated levels of inflammatory cytokines. These cytokines play important roles in the immune system. They are signaling proteins that help trigger inflammation.

For example, HS-related skin lesions contain elevated levels of the following cytokines:

  • tumor necrosis factor-alpha (TNF-a)
  • interleukin-1 beta (IL-1b)
  • interleukin-17 (IL-17)
  • interleukin-23 (IL-23)
  • several other types of interleukins

Scientists have also found unusually high levels of other inflammatory proteins in the skin and blood of people with HS.

Biologics are a class of medications that mimic normal molecules in living organisms or cells.

They often contain proteins that help turn certain parts of the immune system on or off.

For example, some biologics block the action of certain inflammatory cytokines or other molecules that help drive inflammation. This helps interrupt immune processes that produce inflammation.

Some biologics block cytokines or other mediators of inflammation that appear to play a role in HS. This may help reduce disease activity, ease the symptoms, and minimize scarring.

For example, adalimumab (Humira) is a type of biologic that blocks TNF-a. It is known as a TNF-a inhibitor. In phase III clinical trials, roughly 40–60% of people with HS who received Humira showed considerable improvements in symptoms.

“You use something like Humira to block the [immune] signal that’s on overdrive and perpetuating inflammation in the skin,” Dr. Adam Friedman, a professor and interim chair of dermatology at the George Washington University School of Medicine and Health Sciences in Washington, D.C., told MNT.

Studies suggest that it may also be helpful to treat certain cases of HS with ustekinumab (Stelara). This biologic inhibits IL-12 and IL-23. In a phase II trial, roughly 47% of people with HS who received Stelara showed signs of a clinical response.

Clinical trials are also underway to study the use of other biologics to treat HS. This includes the IL-17 inhibitor secukinumab (Cosentyx) and the IL-23 inhibitor guselkumab (Tremfya).

Scientists need to conduct more research to assess and compare the potential benefits and risks of using different types of biologics to treat HS. Some people with HS experience more benefits from certain biologics than others.

To date, the Food and Drug Administration (FDA) have only approved one type of biologic to treat HS: Humira. The FDA have approved this TNF-a inhibitor to treat moderate-to-severe cases of HS in adults. To administer this medication, a person injects it under their skin.

Sometimes, a doctor may prescribe another type of biologic that the FDA have not approved to treat HS. This is known as an off-label prescription.

For example, a doctor may prescribe one of the following off-label biologics for HS:

  • infliximab (Remicade), which is another type of TNF-a inhibitor
  • Stelara, which is an IL-12/IL-23 inhibitor
  • Cosentyx, which is an IL-17 inhibitor
  • Tremfya, which is an IL-23 inhibitor
  • Kineret or Xilonix, which are IL-1 antagonists

A doctor may prescribe an off-label biologic if a person has already tried Humira and it did not work well for them. In some people, Humira is not effective for treating HS. Sometimes, this medication appears to work well at first but becomes less effective over time.

A doctor may also prescribe an off-label biologic if a person has certain health conditions that make it less safe to prescribe Humira, such as multiple sclerosis (MS) or heart failure.

“One of the contraindications for use [of TNF-a inhibitors] is demyelinating diseases like MS,” Dr. Friedman said, “because it’s been shown that these kinds of drugs can actually make the disease worse.”

Biologics suppress the immune system. As a result, they increase the risk of infections. They may also cause other side effects, which range from mild to potentially severe.

For example, common side effects of taking Humira include:

  • flushing, swelling, bruising, itching, or pain around the injection site
  • upper respiratory infections
  • headaches
  • rash

In rare cases, people taking Humira have developed:

  • serious infections, such as tuberculosis or invasive fungal infections
  • lymphoma, which is a type of cancer that affects the lymph system
  • serious allergic reactions
  • demyelinating disease
  • lupus-like syndrome
  • low blood count
  • heart failure

Other types of biologics may also cause side effects. In some cases, these side effects may be severe. To learn more about the potential benefits and risks of a particular biologic, a person can speak to their doctor.

“Biologics can be a life changing therapy for individuals with HS. However, like any medication, there are risks,” Dr. Frew told MNT, “and the risks need to be weighed against the potential benefits to the individual.”

A doctor should conduct a thorough medical history and physical examination before they prescribe a biologic to a patient. If the patient has certain health conditions or risk factors for side effects, the doctor may advise them to avoid treatment with certain biologics.

“Full-body examination, blood work, and testing for infectious diseases such as tuberculosis, as well as discussion regarding the risks and expected benefits, should be done before starting any biologic medication,” Dr. Frew advised.

HS causes painful skin lesions. Over time, serious infections and scarring may develop. This can have significant effects on a person’s comfort and quality of life.

To treat HS, doctors can prescribe a variety of treatments. For example, they may recommend a combination of lifestyle changes, surgical treatments, and medications. These medications may include a biologic, as well as other topical, oral, or injectable therapies.

To learn more about the potential benefits and risks of using a biologic to treat HS, a person can speak with their doctor. The doctor can help them understand the role that biologics play in managing HS.