SCIg for Primary Immunodeficiency: Troubleshooting Swelling, Redness, and Pain at the Infusion Site

For people living with primary immunodeficiency (PI), immunoglobulin replacement therapy is an essential part of preventing serious infections. The treatment can be delivered through an IV (intravenously), usually in a healthcare setting, or with SCIg (subcutaneous immunoglobulin), which is infused at home using small needles inserted just under the skin.

SCIg offers flexibility and steady antibody levels, but local infusion-site reactions are common, especially early in treatment or when routines change. Understanding what’s normal, what may signal a problem, and when to reach out for help can make self-infusion safer and more comfortable over time.

A typical SCIg site reaction looks like a small bubble of fluid under the skin, with pink or slightly warm skin over the infusion area, called induration, says Danielle Nance, MD, a hematologist with Banner Health in Gilbert, Arizona.

“This swelling should gradually shrink over the hours after the infusion, while redness may last up to 48 hours as the medication is absorbed,” says Dr. Nance.

Normal reactions may also include:

• Mild to moderate swelling at the infusion site
• Pink or slightly warm skin
• Mild tenderness or itching

Concerning reactions tend to be more painful and longer-lasting and could be signs of an infection, which should be checked out by a healthcare provider.

Although a certain level of skin reaction to an infusion is expected, if you’re experiencing bothersome swelling or redness that lingers, there are strategies that may help.

Adjusting Volume or Rate per Site

How much immunoglobulin goes into each infusion site and how quickly it’s delivered can make a big difference in how swollen or sore the area feels afterward.

When a large volume of medication is delivered into one site, or when it flows in too quickly, the surrounding tissue may stretch faster than it can comfortably absorb the fluid. This can lead to more noticeable swelling, pressure, or pain at the infusion site.

These changes aren’t something you should do on your own, though. Because infusion pumps vary by manufacturer, and each SCIg product has specific limits for flow rate and volume per site, you should talk with your nurse about any adjustments to ensure safety and efficacy, says Megan Ehret, PharmD, a professor in the department of practice, sciences, and health outcomes research at the University of Maryland School of Pharmacy in Baltimore.

Warming the Product Safely

Allowing SCIg to reach room temperature before infusion is important for a few reasons. It reduces the pressure required for infusion, which reduces pain at the site. Warmer immunoglobulin is also closer to normal body temperature, and so it naturally feels more comfortable than a cold fluid when entering your body.

Most products should be removed from the refrigerator and allowed to sit at room temperature for at least 30 minutes before use, but your nurse may recommend longer — an hour or even more. Check the label for specific instructions, because each product has specific limits for how long it can safely remain unrefrigerated.

You should not attempt to warm the product using methods such as microwaves, hot water, or heating devices, as they can damage the medication, says Ehret.

Rotating Sites Effectively

Rotating, or changing, infusion sites for each infusion helps protect the skin and reduce irritation over time. There is no single “right” rotation pattern, says Ehret.

Common infusion sites include:

• The abdomen
• Thighs
• Upper arms
• The sides of the hips or upper legs

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“Sites should be places you are comfortable using and should be placed at least one inch away from the previous infusion site,” she says.

Areas that are already red, bruised, painful, hard, or irritated should be avoided. Reusing the same spot repeatedly can increase swelling and discomfort and slow healing between infusions.

While mild infusion-site reactions can be managed at home, there are also more concerning symptoms that should be discussed with your provider or nurse, says Nance.

Signs that should prompt a call include:

• A very large bubble of fluid that shrinks and then returns
• Increasing pain at the infusion site
• Leakage, weeping, or fluid coming from the injection site
• Fever higher than 101 degrees that lasts more than six hours
• Headache, chills, and nausea that don’t improve 24 to 48 hours after the infusion

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If you feel that your infusions aren’t going well, your side effects aren’t improving even after making some adjustments, or you're simply feeling overwhelmed by the responsibility of self-infusion, reach out to your provider or nurse, says Nance.

“Those are all valid reasons to reach out. Additional nurse visits or check-ins can help you feel more confident and supported during the transition to home SCIg,” she says.

• Mild swelling, redness, warmth, or tenderness at SCIg infusion sites is common and usually improves within 24 to 48 hours.
• Warming the product, rotating sites, and adjusting infusion rate or volume with nurse guidance may reduce discomfort.
• Symptoms that don’t go away in 48 hours including spreading redness, worsening pain, fluid leaking from the site, or fever higher than 101 degrees should be discussed with your nurse or healthcare provider right away.