What to Know About Dupixent for Allergic Fungal Rhinosinusitis

Written by Patricia Weiser, PharmD
Medically Reviewed by Beth Johnston, BCPS, PharmD on March 03, 2026

Allergic fungal rhinosinusitis (AFRS) is a long-term inflammatory sinus condition. It happens when fungus, such as mold, grows in your nasal passages and your immune system has a strong allergic reaction to it.

AFRS can affect both children and adults and is more common in warm, humid areas where mold grows easily. Symptoms may include nasal swelling, nasal polyps, thick mucus, constant congestion, blocked sinuses, and loss of smell (which can also affect taste). In more severe cases, it can damage the bones around the sinuses and even change the shape of your face.

The main treatment for AFRS is surgery. Sinus surgery removes nasal polyps and thick mucus and helps open the sinuses. After surgery, people often need to use steroid medicines (nasal sprays and/or medicines taken by mouth). Despite these treatments, symptoms often return.

In February 2026, the FDA approved Dupixent (dupilumab) as the first treatment specifically for AFRS in people who have already had sinus surgery. This article answers common questions about Dupixent for AFRS and what you can expect from treatment.

No, Dupixent is not a steroid. Dupixent is a type of biologic medicine and belongs to a class of medicines called interleukin (IL) receptor antagonists.

Fungal spores can become trapped in sinus mucus. In some people, this leads to ongoing type 2 inflammation. Type 2 inflammation is a pattern of immune system overactivity often linked to allergies and conditions such as nasal polyps. It involves certain immune signals and cells that cause swelling, excess mucus, and tissue damage. The body also produces higher levels of immunoglobulin E (IgE), which is a type of antibody your immune system makes when it overreacts to an allergen.

Two of the main immune signals involved in type 2 inflammation are IL-4 and IL-13. These signals activate immune cells, including eosinophils, and increase the release of substances that lead to swelling and thick mucus in the sinuses.

Dupixent is designed to target this pathway. It attaches to a shared receptor (binding site) that IL-4 and IL-13 use to send inflammatory signals. By blocking this receptor, Dupixent helps stop IL-4 and IL-13 from driving type 2 inflammation. While the exact way Dupixent works in AFRS is not fully known, it is thought to reduce inflammation by targeting these two key signals.

Dupixent comes as a liquid in a single-dose prefilled pen or prefilled syringe. It is given as an injection under the skin (subcutaneous). With proper training, you or a caregiver may be able to give the injections at home.

Your health care provider will show you how to prepare and inject Dupixent. To review the steps, refer to the Instructions for Use that comes with your prescription. Children who are 12 years or older may inject Dupixent themselves under adult supervision. For children younger than 12 years, a caregiver should give the injection.

Before each dose, remove the medicine from the refrigerator and let it reach room temperature. The 300 milligram (mg) pen or syringe should sit out for about 45 minutes. The 200 mg pen or syringe should sit out for about 30 minutes. Always check the liquid before using it. It should be clear to slightly yellow and free of particles. If it looks cloudy or discolored, do not use it.

Dupixent can be injected into your thigh or stomach area, except for the 2 inches around your belly button. If a caregiver is giving the injection, it can also be given in the outer area of the upper arm. You should rotate injection sites each time. Do not inject into skin that is tender, bruised, damaged, or scarred.

For adults with AFRS, the recommended dosage of Dupixent is 300 mg every two weeks.

For children aged 6-17 years with AFRS, the recommended dosage of Dupixent depends on body weight:

  • Children who weigh 33 to less than 66 pounds (15 to less than 30 kilograms) receive 300 mg every four weeks.
  • Children who weigh 66 to less than 132 pounds (30 to less than 60 kilograms) receive 200 mg every two weeks.
  • Children who weigh 132 pounds (60 kilograms) or more typically receive the same dosage as adults, which is 300 mg every two weeks.

Ask your health care provider or pharmacist if you have questions about your dosage or how to use Dupixent.

A study called the LIBERTY-AFRS-AIMS trial was done to test how safe and effective Dupixent is for adults and children who are 6 years or older with AFRS. The study lasted 52 weeks (one year). In this study, adults and children with AFRS who had already had sinus surgery were randomly assigned to receive either Dupixent or a placebo (an injection with no active medicine). Neither the participants nor the researchers knew who was receiving Dupixent during the study. Doses were given every two or four weeks, depending on the age and body weight.

To join the study, people had to have a confirmed diagnosis of AFRS with moderate to severe sinus blockage seen on a CT scan, along with nasal polyps.

People were not allowed to join the study if they had other serious nasal conditions, such as tumors or invasive fungal disease. Those with significant medical problems, active infections, immune system disorders, or untreated tuberculosis could not participate. Certain recent treatments were not allowed, such as immune-suppressing medicines. People using nasal steroids could join as long as the medicine and dosage had stayed the same for at least four weeks before the study began.

A total of 62 people took part in the study:

  • The average age was about 40 years. Most participants were over the age of 17.
  • Most were male (73%), and 27% were female.
  • Around 44% of the people were White, 40% were Asian, 13% were Black, and 3% were of unknown race or did not report their race.
  • Nearly everyone had at least one sinus surgery in the past, and about half had two or more sinus surgeries.
  • Many people also had asthma or other allergic conditions.

The main goal of the study was to see whether Dupixent reduced sinus blockage on CT scans after 52 weeks. To measure sinus blockage, a scoring system called the Lund-Mackay (LMK) score was used. The scale ranges from 0 to 24. Higher scores mean more severe sinus blockage. Researchers compared each person’s score at the start of the study with their score after one year to see how much it changed.

The study also looked at other changes, such as nasal congestion, nasal polyp size, sense of smell, and whether people needed certain treatments or surgeries.

Overall, the LIBERTY-AFRS-AIMS trial showed that Dupixent was an effective treatment for people with AFRS.

After a year, the main results showed that sinus blockage improved by about 50% in people who received Dupixent, compared with about 10% in those who received placebo.

At the start of the study, sinus blockage scores were similar in both groups (18.45 in the placebo group and 17.50 in the Dupixent group, on a scale of 0 to 24). After 52 weeks:

  • The placebo group improved by 1.81 points.
  • The Dupixent group improved by 9.17 points.
  • On average, people taking Dupixent had a 7.36-point greater reduction in sinus blockage compared with those taking placebo.

Here are some of the other results, on average:

  • Nasal congestion: At 24 weeks, Dupixent reduced nasal congestion score by 0.87 more points than placebo. By 52 weeks, Dupixent lowered nasal congestion scores by 1.40 more points than placebo.
  • Nasal polyps: At 24 weeks, nasal polyp scores decreased by 2.36 more points with Dupixent than with placebo. At one year, Dupixent reduced nasal polyp scores by 2.77 more points compared with placebo.
  • Sense of smell: At 24 weeks, Dupixent improved loss of smell scores by 0.89 points more than placebo.
  • Need for steroids or surgery: Over one year, people taking Dupixent had a 92% lower risk of needing oral steroid medicines or additional sinus surgery. 
    • Only 3% of people on Dupixent needed oral steroids, and none needed surgery.
    • In comparison, 31% of people on placebo needed oral steroids, and 7% needed surgery.

Overall, Dupixent led to much greater improvements in signs and symptoms of AFRS compared with placebo. Keep in mind that your results may vary from study results.

Some people may begin to notice symptom relief within the first few weeks of starting Dupixent. In the clinical study, nasal congestion scores were already lower in people taking Dupixent compared with placebo by week 4, and improvement continued over time.

Individual responses can vary. Talk with your health care provider about what to expect.

Most people tolerate Dupixent well, but side effects are possible. In the study of Dupixent for AFRS, the most commonly reported side effects were injection site reactions, trouble sleeping, toothache, stomach irritation (gastritis), joint pain, and eye problems ​​(such as redness, swelling, itching, or blurred vision).

Mild side effects can often be managed at home, but it is important to let your health care provider know if your symptoms get worse or do not go away.

For injection site reactions, rotate where you give each injection and avoid skin that is bruised, tender, or damaged. Let the medicine sit at room temperature before injecting. A cool compress may help reduce redness or swelling.

Eye symptoms are fairly common while using Dupixent. For mild eye irritation or dryness, you could try:

  • Over-the-counter (OTC) preservative-free artificial tears 
  • A cold compress for comfort
  • For eyelid irritation, try a warm compress or gentle eyelid scrubs

If you notice blurred vision, eye pain, worsening redness, or discharge, contact your health care provider or eye specialist. You may need prescription eye medicine.

Other tips:

  • For joint pain, ask your health care provider whether an OTC pain reliever is right for you.
  • If you have stomach irritation, try to eat smaller meals, avoid spicy or acidic foods, and stay upright after eating. 
  • If you have trouble sleeping, try to limit caffeine later in the day, create a calming bedtime routine, and try to go to bed and wake up at the same time every day.
  • For toothache, maintain good oral hygiene, try a toothpaste for sensitive teeth, and schedule a dentist appointment if pain continues.

This is not a complete list of Dupixent side effects. Tell your health care provider if the side effects feel severe, worsen, or do not improve.

A cost assistance program is available from Sanofi-Aventis, the maker of Dupixent. Whether you qualify to enroll may depend on what type of insurance you have or if you are uninsured. For more information about Dupixent financial support options, visit this website or call 844-387-4936.

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