If you’re new to using an injectable medication for eczema at home, it can be hard to know what’s normal and what isn’t. Although not everyone develops a lump or knot at the injection site, you should know what can cause it, when you should contact your doctor, and how to prevent it.

Injectables for Eczema

Your dermatologist may prescribe an injectable for eczema if you have uncontrolled moderate to severe atopic dermatitis (the most common subtype of eczema). This usually means that your eczema hasn’t responded to topical therapies, but your situation may be different.

Prescription injectables for eczema belong to a class of medications called biologics. These medicines are made from living cells and work by targeting certain parts of the immune system. The U.S. Food and Drug Administration (FDA) has approved four injectable medications to treat moderate to severe eczema:

• Dupilumab (Dupixent) — For use in adults and children 6 months and older
• Lebrikizumab-Ibkz (Ebglyss) — For use in people 12 years and older who weigh at least 88 pounds
• Nemolizumab (Nemluvio) — For use in people 12 years and older, to be used simultaneously with either topical corticosteroids or calcineurin inhibitors
• Tralokinumab-ldrm (Adbry) — For use in people 12 years and older

These four biologics all work by blocking the effects of immune proteins called interleukins (ILs), which can create skin inflammation, leading to eczema. You may also hear interleukins referred to as cytokines — interleukins are a specific type of cytokine. Dupilumab blocks the effects of two specific interleukins, IL-4 and IL-13. Tralokinumab-ldrm and lebrikizumab-Ibkz block the effects of IL-13 only. Nemolizumab blocks the effects of a different interleukin, IL-31.

All four medications are given subcutaneously (beneath the skin). You can inject these medications on your own at home or in your doctor’s office.

Common Side Effects of Biologics for Eczema

Discoloration, itching, and swelling at the injection site are among the most common side effects of biologics. Eye problems such as conjunctivitis (pink eye) and blepharitis (eyelid inflammation) are common side effects, too.

Dupilumab is also associated with an increased risk of oral herpes (cold sores). Tralokinumab-ldrm and nemolizumab can cause other side effects like upper respiratory tract infections (such as the common cold) and high levels of eosinophils (a type of white blood cell). Finally, lebrikizumab-Ibkz may cause headaches in some people.

Several MyEczemaTeam members have shared that they didn’t experience any side effects from a biologic injection. “I have injections every two weeks — no side effects,” one member said.

What Can Cause a Lump at the Injection Site?

Lumps aren’t specifically listed as a possible side effect of these drugs. However, some of the other side effects of biologics could cause you to feel a lump at or near the injection site.

Wheal Formation

If you notice a raised area of skin immediately after your injection, it could be a wheal (welt). A wheal can result when injected liquid medication causes the skin to rise. It may take some time, especially with larger volumes of medication, for the drug to be absorbed into your bloodstream after it’s injected.

For most people, this effect should fade within a few hours after the injection. If the wheal doesn’t go away, talk to your doctor.

Injection Site Reaction

Injection site reactions are one of the most common side effects of injectables for eczema. For example, in clinical trials, injection site reactions occurred in about 10 percent of people using dupilumab and about 7 percent of people using tralokinumab-ldrm.

Injection site reactions are localized, which means the side effect is limited to the area around the injection, not your whole body. The symptoms of an injection site reaction include:

• Discolored skin
• Pain
• Bruising
• Swelling
• Itching

You may notice these symptoms shortly after your injection, and they can last three to five days.

Let your doctor know if your symptoms don’t get better after a few days or if they worsen. For example, if the injection site starts to drain fluid or pus or the area feels warm to the touch, you may have developed an infection.

Lipohypertrophy

If you notice a lump of fatty tissue under your skin in the same place that you usually inject your medication, you may have lipohypertrophy. An area affected by lipohypertrophy may feel firmer than the tissue around it and might be:

• Lumpy
• Raised
• Thick
• Rubbery
• Swollen
• Numb

Lipohypertrophy is typically caused by injecting medication into the same area of the skin too often. Although lipohypertrophy usually doesn’t spread, the lump can get bigger over time if you continue to inject medication in the same place. You may also find lumps in other areas you inject.

There isn’t any information about how often lipohypertrophy may happen in people using biologics for eczema. However, this skin disorder is common in people with diabetes who inject insulin subcutaneously every day.

A lump caused by lipohypertrophy shouldn’t feel painful or hot to the touch. If you have these symptoms or notice any bruising or discoloration in the area, you should seek medical advice right away. These could be signs of a new skin condition or rash.

Treatment for Lumps at the Injection Site

Your treatment will depend on what’s causing the lump. If the lump results from an injection site reaction, your doctor may recommend supportive treatments. You can take antihistamines to help control rashlike symptoms such as discoloration and itching.

If you have any pain, your doctor may recommend a pain reliever, like acetaminophen (Tylenol). Applying an ice pack or cold compress may also bring relief.

If a lump is caused by a skin infection, you may need to take a course of antibiotics or have your abscess drained. Some types of lumps, such as wheals or lipohypertrophy, may not call for any specific treatment.

Preventing Lumps at the Injection Site

Try the following tips to help prevent lumps at the injection site:

• Study the materials that came with your medication to make sure you understand the proper administration technique. Ask for help from your doctor, nurses, or pharmacist if you have any questions.
• Rotate your injection site, alternating spots around your belly button and thighs.
• Practice good hygiene. Prevent infections by washing your hands with soap and water and cleaning the area with alcohol before you inject.

Other Treatment Options

If you have troubling side effects from an injectable medication for eczema, talk to your doctor about other treatment options. You may need to stop or change medications if you have an allergic reaction or another adverse effect from injectable medications. Other prescription treatment options for moderate to severe eczema include:

• Oral and topical Janus kinase (JAK) inhibitors
• Oral corticosteroids
• Topical calcineurin inhibitors
• Topical corticosteroids
• Phototherapy (light therapy)

Your healthcare provider can help you find the treatment plan that will help you achieve the best results with the fewest side effects.

Talk With Others Who Understand

MyEczemaTeam is the social network for people with eczema and their loved ones. On MyEczemaTeam, more than 55,000 members come together to ask questions, give advice, and share their stories with others who understand life with eczema.

Have you felt a lump where you inject your medication? Have you taken steps to keep lumps from forming at your injection site? Share your experience in the comments below, or start a conversation by posting on your Activities page.