What Is Hives?
Hives (urticaria) are raised, well-defined, often intensely itchy welts that can appear anywhere on the body. A hallmark feature is that individual hives tend to come and go — a welt may fade within hours while new ones appear elsewhere, giving the rash a shifting quality over the course of a day.
Hives are classified as acute (lasting less than six weeks, often tied to a clear trigger) or chronic (lasting more than six weeks, frequently without an identifiable cause). Both forms are very treatable, even when no specific trigger is ever found.
Causes
- Allergic reactions to foods, medications, or insect stings
- Viral or other infections
- Physical triggers: pressure, cold, heat, sun exposure, or exercise
- Chronic idiopathic urticaria, where no specific trigger is identified despite thorough evaluation
Symptoms
- Raised, pink or red welts of variable size and shape
- Intense itching
- Individual welts that fade within 24 hours, though new ones may continue to appear
- Possible mild swelling in surrounding skin
Treatment Options at Dermatology of Seattle
- Antihistamines, often at higher-than-standard doses for stubborn cases
- Identifying and avoiding triggers when a clear cause is found
- Additional prescription options for chronic hives that don't respond to antihistamines alone
- Evaluation for underlying causes when hives are chronic or recurring
When to See a Dermatologist
See a dermatologist if hives last more than a few days, recur frequently, or don't have an obvious trigger. Seek emergency care immediately if hives appear along with swelling of the lips, tongue, or throat, difficulty breathing, dizziness, or vomiting — these can be signs of a severe allergic reaction (anaphylaxis).
Frequently Asked Questions
Are hives dangerous?
Hives on their own are usually not dangerous, though they can be uncomfortable and disruptive. In rare cases, hives can accompany a severe allergic reaction with swelling and breathing difficulty, which is a medical emergency requiring immediate care.
What's the difference between acute and chronic hives?
Acute hives last less than six weeks and often have an identifiable trigger, like a food or medication. Chronic hives last longer than six weeks and frequently occur without a clear cause, though they're still very manageable with the right treatment plan.
Why do I keep getting hives with no obvious cause?
This is common with chronic idiopathic urticaria, where despite testing, no specific trigger is identified. A dermatologist can still help manage symptoms effectively with a structured treatment approach, even without pinpointing an exact cause.