Overview
COVID arm refers to a delayed hypersensitivity reaction that can occur 7 to 10 days after receiving a COVID-19 vaccine. It appears as a red, itchy, warm, or swollen rash near the injection site. While it can be concerning, it is a harmless immune response and is not a sign of infection or vaccine allergy.
Symptoms
Symptoms include a large, red, and warm patch of skin on the arm where the shot was given. It may be itchy, tender, or painful. It usually peaks around day 7-10 and resolves within a few days. It is not accompanied by fever or other systemic symptoms.
Causes
The exact cause is not fully understood but it is thought to be a delayed T-cell mediated immune response to the vaccine's ingredients, particularly to the polyethylene glycol (PEG) in mRNA vaccines. It indicates that the body is building an immune response.
Treatment
Treatment is usually not needed as it resolves on its own. Applying a cool compress can help reduce itching and swelling. If the reaction is bothersome, an oral antihistamine or a topical corticosteroid cream may be used.
When to See a Doctor
Consult a doctor if the rash is accompanied by signs of a severe allergic reaction (like trouble breathing, rapid heartbeat, or dizziness), or if it doesn't resolve within a week or becomes very painful.