Hives are a common skin reaction that can be caused by viral infections. They often appear as part of the body’s response to an invading virus.
What Are Hives?
Hives, medically known as urticaria, are raised, itchy welts that appear on the skin. These bumps can be red or skin-colored, varying in size. They often appear in batches, can change shape, move around the body, and typically fade within 24 hours, though new ones may emerge. Red hives blanch, or turn white, when pressed.
While viruses can trigger hives, many other factors can also cause them. Common non-viral causes include allergic reactions to foods, medications, or insect bites. Physical stimuli such as pressure, cold, heat, exercise, or stress can also lead to hives. In many instances, the specific cause of hives remains unidentified.
How Viruses Trigger Hives
Viral infections can lead to hives through the body’s immune response. When a virus enters the body, the immune system activates to fight the infection. This activation causes immune cells to release chemicals like histamine into the bloodstream. Histamine is responsible for many of the symptoms associated with hives, including itching, redness, and swelling.
The release of histamine causes blood vessels to dilate and become more permeable, allowing fluid to leak into the surrounding skin tissue, which results in raised welts. This immune system activation can happen while a person is actively sick or shortly after they have recovered from the viral infection. Sometimes, hives can be the only noticeable sign that the body is fighting a viral infection, even without other typical symptoms like fever or cough.
Common Viral Infections Linked to Hives
Many viral infections can trigger hives. Common viral illnesses like the common cold and influenza (flu) are frequently associated with hives in children and adults. While hives are not a primary symptom of the flu, they can occur, sometimes even as the sole symptom, though this is uncommon.
Mononucleosis, caused by the Epstein-Barr virus (EBV), is another viral infection that can lead to hives. While a typical mono rash is often non-itchy and maculopapular, EBV can also trigger an immune response resulting in hives. Roseola, a common childhood viral illness, can also cause a rash that sometimes resembles hives. Measles and rubella can also present with skin rashes, including hive-like eruptions. COVID-19 has also been linked to hives, which can appear early in the infection and typically resolve within days to weeks.
When Hives Are Caused by a Virus
Hives caused by viral infections generally resolve as the underlying viral illness clears. Symptomatic relief can help manage discomfort. Over-the-counter antihistamines are often recommended to alleviate itching and swelling. Applying cool compresses or taking cool baths can also provide relief.
While most cases of virally induced hives are not serious, it is important to know when to seek medical attention. Immediate care is necessary if hives are accompanied by difficulty breathing, wheezing, swelling of the face, lips, or tongue, or light-headedness or fainting. These could be signs of a severe allergic reaction called anaphylaxis, which requires emergency treatment. Medical consultation is also advised if hives are widespread, severe, persistent for more than a few days, or recur frequently.