You may have had what experts refer to as a corticosteroid flare. In a small number of patients, the body reacts negatively to the injection. Local irritation in the form of pain and/or a skin rash occurs.
This response occurs within the first eight to 24 hours after injection. The benefits of the injection (pain relief and reduced inflammation) are usually still experienced.
No one is sure just why this reaction occurs. It may be an immune reaction to the preservative in the product. Or it may be a response to the corticosteroid. Some experts have suggested needle penetration into nerve endings may be the cause. Others say that if this were the cause, then more patients would have the flare reaction.
When corticosteroid flare occurs, ice can be applied to the injection site. Your doctor may prescribe anti-inflammatory medications and analgesics (pain relievers). Analgesics used for this problem may include narcotic medications.