What are hives? Causes, symptoms, treatment, diagnosis, complications, and prevention

Written by Nicolas Perez Diaz, May 20, 2023.

Hives, also known as urticaria, is a type of skin rash that appears as red, itchy welts. They can appear anywhere on the body and may vary in size, from small dots to large patches. Hives are usually the result of an allergic reaction which triggers the release of histamine, a chemical that causes blood vessels to leak fluid into the skin.

Causes of hives

This type of skin rash can be caused by a number of things, such as:

  • Allergic reactions

Certain foods, medications, insect bites or stings, and environmental factors can trigger reactions in vulnerable individuals.

The American Academy of Dermatology says the following about allergic reactions:

“When hives are due to an allergic reaction, it’s often an allergy to a food, bug bite or sting, latex, medication, pet dander, plant, and pollen.”

  • Physical triggers

Common triggers include exposure to extreme cold or heat, pressure on the skin, or excessive sweating.

  • Infections

Some viral or bacterial infections can cause hives, including the common cold, hepatitis, or strep throat.

  • Underlying medical conditions

Skin rashes may be a symptom of illnesses like autoimmune disorders, thyroid conditions, or certain cancers.

Signs and symptoms

The primary symptom of hives is the appearance of raised, itchy welts on the skin. But there are other symptoms, which include:

  • Red or pink-colored patches on the skin.
  • Swelling around the hives.
  • Welts that may change shape and size, merging together to form larger areas known as plaques.
  • Burning or stinging sensation on the affected skin.
  • They can occur in any part of the body, including the face, lips, tongue, throat, or ears.

According to everydayhealth.org:

“Hives and itching often worsen at night because that’s when the body’s natural anti-itch chemicals are at their lowest.”

Interesting related article: “What’s the difference between a sign and a symptom?”


Your doctor will probably ask about your signs and symptoms, how long you have had them, when they tend to occur, your medical history, and carry out a physical examination.

They may also order blood tests and/or an allergy skin test.

Hives - three images depicting the skin rash

Created by MedicalVocab.com using Wikimedia Commons images.

Treatment for hives

Treatment focuses on relieving symptoms and addressing the underlying cause. They may include:

  • Over-the-counter antihistamines

Non-drowsy OTC antihistamines like loratadine and cetirizine can help reduce itching and swelling brought. Most pharmacies have these medications in stock. The letters OTC stand for over the counter. We can buy OTC drugs without a doctor’s prescription; they contrast with prescription medications (see below).

  • Prescription medications

In severe cases, a doctor may prescribe stronger antihistamines, corticosteroids, or immune-suppressing drugs to alleviate symptoms.

  • Avoiding triggers

Identifying and avoiding the triggers is essential. Keeping a diary to track potential triggers can be helpful

According to medicalnewstoday.com:

“Benadryl is effective for decreasing itchy skin from hives. It’s often considered a first-choice treatment for hives.”


Hives cannot always be prevented, but certain measures can reduce the risk of occurrence:

  • Identify triggers

Pay attention to potential triggers and try to avoid them. Potential triggers may include specific foods, medications, or environmental factors.

  • Protect the skin

Wear loose-fitting clothes, use sunscreen, and practice good skin hygiene.

  • Allergy testing

If you suspect that an allergy is the cause, see your doctor or consult an allergist for testing to identify specific allergens