Hives

Hives are small, pale red swellings on the skin, occurring singularly or in clusters. They tend to fade after a few hours, but new ones can appear. Most cases of hives resolve within a few days, but some can take a few weeks.

Causes

Hives are caused by a reaction in which certain cells of the body release a substance called histamine. The cause of the reaction may be known or unknown and could include:
  • Foods, most commonly:
    • Eggs
    • Shellfish
    • Nuts
    • Chocolate
    • Fish
    • Tomatoes
    • Fresh berries
    • Milk
  • Drug allergy
  • Reaction to allergy shots (desensitization shots)
  • Infections
  • Insect bites or stings
  • Latex
  • Disease
  • Pressure
  • Cold
  • Sunlight
  • Thyroid disease

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.
  • Exposure to substances that may cause hives
  • Exposure to situations that may cause hives

Symptoms

The symptoms of Hives can vary from mild to severe.
Symptoms include:
  • Itchiness
  • Redness
  • Swelling
  • Excessive swelling of the eyes, lips, or genitals
  • Burning
  • Stinging
  • Difficulty breathing or swallowing (Seek immediate medical care if you have this symptom.)

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam. You may be referred to a doctor who specializes in skin disorders (dermatologist) and/or allergies (allergist).

Treatment

The best way to treat hives is to identify and avoid the cause.
Medications for treating hives include:
  • Over-the-counter antihistamines such as:
    • Diphenhydramine
    • Hydroxyzine
    • Cyproheptadine
  • Prescription antihistamines such as:
    • Fexofenadine (Allegra)
    • Loratadine (Claritin)
    • Acrivastine (Semprex)
    • Cetirizine (Zyrtec)
  • H2 blocking medications such as:
    • Cimetidine
    • Ranitidine
    • Famotidine
  • Steroid skin creams
  • Oral medications (prednisone) for hives resistant to other treatments
  • Prescription epinephrine (adrenalin) in rare cases if swelling affects airways

Prevention

The best way to prevent Hives is to avoid substances or situations that have caused you to get Hives in the past.