The COVID-19 vaccines can lead to various reactions, and among them, hives are a possible, though generally uncommon and mild, occurrence. While most reactions are temporary and resolve without lasting issues, understanding these responses can help individuals manage their health post-vaccination.
Understanding Hives After Vaccination
Hives, medically known as urticaria, are characterized by itchy, red welts that can appear on the skin. These raised areas can vary in size and shape, often blanching (turning white) when pressed. They may appear anywhere on the body, including the arms, trunk, and legs.
Skin reactions, including hives, can occur after COVID-19 vaccination. These reactions can manifest either immediately, within hours, or with a delayed onset, appearing days to weeks later. Delayed reactions, such as “COVID arm” near the injection site, are generally benign and do not typically indicate a severe allergy.
How Hives May Develop
The development of hives following a COVID-19 vaccine is primarily an immune system response. The body’s immune system can react to components within the vaccine, leading to the release of histamine and other mediators that cause the characteristic skin welts.
It is important to distinguish between a true allergic reaction and other immune responses. A true allergic reaction is typically immediate and involves specific antibodies, often to a vaccine component like polyethylene glycol (PEG) or polysorbate 80. However, many delayed skin reactions, including hives, are not true allergies. They are considered a side effect of the vaccine’s immune activation as the body builds protection.
What to Do If Hives Occur
If hives develop after COVID-19 vaccination, the course of action depends on the severity and accompanying symptoms. For mild, localized hives without other symptoms, self-care can provide relief. Applying cool compresses and taking over-the-counter antihistamines can help manage the itching and rash. Most mild hives resolve within a few days to weeks.
Recognize the signs of anaphylaxis, a severe allergic reaction requiring immediate medical attention. Symptoms include difficulty breathing, wheezing, swelling of the face, lips, or throat, a drop in blood pressure, or dizziness. While hives can be a symptom of anaphylaxis, they are typically accompanied by these more serious signs. If any severe symptoms occur, seek emergency medical care. For persistent, widespread hives, or any other concerning symptoms, consulting a healthcare provider is advised for proper evaluation and guidance.
Considerations for Future Doses
Individuals who experience hives after a COVID-19 vaccine should discuss their reaction with a healthcare provider. For mild, delayed hives, a subsequent vaccine dose is often recommended. The healthcare provider might suggest receiving the next dose in the opposite arm or under extended observation for 30 minutes.
For those who experienced an immediate or severe reaction, an allergist’s guidance is essential to determine the cause and safest path forward. A severe allergic reaction to a prior dose of a specific vaccine type generally contraindicates another dose of that same type. However, an alternative vaccine type might be an option. Healthcare providers assess the risks and benefits, noting that the protective benefits of COVID-19 vaccination generally outweigh the risks of a mild vaccine reaction.