Post Injection Inflammatory Reaction

Post Injection Inflammatory Reaction is swelling, irritation, and other problems that can develop after a person gets a shot (injection). The reaction can develop at and around the injection site or far away from the injection site.

In some cases, it can develop right away and last for a short period of time. In other cases, it can develop weeks after the injection and last for several hours or days.

What are the causes?

This condition may be caused by:

• An allergy.
• A response by your body’s defense system (immune response).
• Damage to the surrounding tissue from the injection.
• Germs that enter the body through the injection site.

What are the signs or symptoms?

Symptoms of this condition include:

• Itchiness.
• Redness.
• Rash.
• Warmth.
• Swelling.
• Tenderness.
• Pain.
• Fever or chills.
• Muscle aches.
• Nausea or vomiting.
• Loss of appetite.
• Headache.
• Dizziness.

In severe cases, seizures, asthma, or a severe allergic reaction (anaphylaxis) can occur. These cases are rare.

How is this diagnosed?

This condition may be diagnosed with a physical exam. During the exam, a circle may be drawn around the injection site. The circle helps to show whether redness in the area is spreading.

How is this treated?

Treatment for this condition depends on what caused the reaction and how severe the reaction is. Treatments commonly involves:

• Putting an ice pack over the injection site.
• Taking a nonsteroidal anti-inflammatory drug (NSAID) to reduce swelling and itching.
• Taking an antibiotic medicine.
• Taking pain medicine.

If the reaction affects a joint, you may also need to rest that joint for a while.

Follow these instructions at home:

• Keep the injection site clean.
• Take over-the-counter and prescription medicines only as told by your health care provider.
• If you were prescribed antibiotic medicine, take or apply it as told by your health care provider. Do not stop taking or applying the antibiotic even if your condition improves.
• If directed, apply ice to the injured area:
  • Put ice in a plastic bag.
  • Place a towel between your skin and the bag.
  • Leave the ice on for 20 minutes, 2–3 times per day.
• If the reaction affects a joint, rest your joint. Ask your health care provider when you can start to use your joint again.
• Do not drive or operate heavy machinery while taking prescription pain medicine.
• Keep all follow-up visits as told by your health care provider. This is important.

Contact a health care provider if:

• Your symptoms last for several hours.
• You develop a fever or chills.
• You develop muscle aches.

Get help right away if:

• Your symptoms get worse.
• You have trouble breathing.
• You have seizures.