Hives — those red, raised, itchy welts that can appear seemingly out of nowhere — are one of the more alarming things parents encounter. For families in Robbinsville, Allentown, Bordentown, Princeton area, and across Mercer County, allergy season brings a spike in calls to our office about mysterious rashes that appear and disappear in hours. The good news: most hives in children are harmless and manageable at home. Here's what every parent should know.

What Do Hives Look Like?

Raised, red or pink welts (wheals) on the skin
Irregular in shape — they can be small dots or large patches and often merge together
Itchy, sometimes intensely so
Changing — individual hives typically last minutes to a few hours, then fade, often appearing in a new location
Can appear anywhere on the body, including the face, trunk, arms, and legs

If a rash has been in the same exact spot for more than 24 hours without moving, it may not be hives — call our office.

Common Triggers of Hives in Children

Hives occur when the immune system releases histamine, causing blood vessels to leak fluid into the skin. Common triggers include:

Allergy Season Triggers - Pollen (tree, grass, and weed pollen) - Mold spores - Insect stings or bites (especially bee and wasp stings) - Contact with certain plants

Foods - Peanuts, tree nuts, shellfish, fish, milk, eggs, wheat, and soy are the most common food triggers - Food-triggered hives typically appear within minutes to 2 hours of eating

Viral Infections - One of the most common causes of hives in young children is a viral infection (like a cold or stomach bug). This type usually resolves when the illness resolves.

Medications - Antibiotics (especially amoxicillin and sulfa drugs) - Ibuprofen (Advil/Motrin) and aspirin - If your child develops hives after starting a new medication, call our office

Other Triggers - Heat, exercise, or sweating (physical urticaria) - Cold temperatures - Stress

In many cases — especially in young children — the specific trigger is never identified. This is common and does not necessarily mean something serious is wrong.

Home Care for Hives

For mild hives without any other symptoms:

Give an antihistamine: Oral diphenhydramine (Benadryl) or cetirizine (Zyrtec) can relieve itching and help hives fade faster. Dosing is by weight — call our office or check the packaging, and always confirm appropriate dosing for your child's age and weight.

Apply cool compresses: A cool, damp cloth on itchy areas provides comfort.

Avoid the trigger: If you suspect a food, medication, or other trigger, eliminate it and note what happened for your doctor.

Dress comfortably: Loose, cool clothing reduces irritation.

Keep skin cool: Heat can worsen hives. Lukewarm baths may help.

Do NOT use cortisone cream on widespread hives — it won't be effective for this type of allergic reaction.

Anaphylaxis Warning Signs — This Is an Emergency

Hives alone are uncomfortable but not dangerous. However, hives can be the first sign of anaphylaxis — a severe, life-threatening allergic reaction. Call 911 immediately and use an epinephrine auto-injector (EpiPen) if prescribed if your child develops any of the following alongside hives:

Swelling of the lips, tongue, or throat
Difficulty swallowing or speaking
Wheezing, coughing, or difficulty breathing
Hoarse voice or stridor (a high-pitched sound when breathing)
Vomiting, severe stomach pain
Pale, gray, or bluish skin
Fainting, dizziness, or loss of consciousness
Feeling of "doom" or extreme anxiety

Do not wait to see if these symptoms improve on their own. Anaphylaxis can progress very rapidly and is life-threatening without epinephrine. After calling 911, lay your child flat with legs raised (unless breathing is difficult), and stay with them until help arrives.

When to Call Our Office vs. When to Go to the ER

Hives are mild, your child is comfortable, and there are no other symptoms
Hives appear and you're not sure what caused them
Hives keep returning over several days or weeks (chronic hives)
You suspect a medication or food triggered the reaction
Hives have not responded to antihistamines after 24–48 hours

Any signs of anaphylaxis (listed above) appear
Hives are accompanied by facial or throat swelling
Your child is having trouble breathing or swallowing
Your child appears very unwell, faint, or confused

Allergy season in New Jersey can be intense, and hives are a frequent visitor in spring and fall. We're here to help you identify triggers, manage reactions, and discuss allergy testing if chronic or recurrent hives are a concern for your child.

Hives (Urticaria) in Children: Causes, Home Care, and When It's an Emergency