Hives (Urticaria): A Sudden Outbreak of Bumps and Raised Patches on the Skin

What are hives?

Hives (medically known as urticaria) is a common skin condition that affects about 20% of people in their lifetime. It is characterized by a sudden outbreak of raised, swollen bumps on the skin that look like mosquito bites. Hives can appear on any part of the skin, they commonly cause itching but also a burning or stinging sensation. Hives can appear alone, but some join together to form a large plaque of hives. 

Causes of hives 

Normally, your body stores a chemical called histamine. When your immune system recognizes the entry of a threat, it releases histamines which can protect you from being seriously infected. 

Hives happen when there is a release of histamine commonly triggered by an allergic reaction, infection, or exposure to cold. However, the exact cause of hives remains a mystery. 

Common triggers include: 

• Allergic reaction to certain food (such as peanuts, nuts, eggs)
• Medication (such as antibiotics, ibuprofen)
• Infection
• Insect stings or bites
• Physical stimuli (such as cold, heat, and sun exposure) 
• Hives can also be a symptom of certain autoimmune conditions, the most common being autoimmune thyroid diseases

Types of hives (urticaria)

Two common types of hives: 

• Acute (short-lived) - hives or swelling that last less than 6 weeks 
• Chronic (long-term) - hives or swelling that last longer than 6 weeks, and recur frequently over months or years. Chronic urticaria can be further categorized into different subtypes including spontaneous or inducible urticaria.

Symptoms of hives

• Batches of red or skin-colored bumps on any part of the skin
• When pressed, the red center of the bump turns white - “blanching”
• Bumps that vary in size, shape
• Itching

What is the difference between Hives and Angioedema?

Hives and angioedema are often mistaken for each other. Angioedema is defined as a deeper form of hives, which occurs deep beneath the skin rather than the surface of the skin. In rare cases, angioedema can take place in the throat or tongue which can block the airway, causing breathing difficulty. This may become a life-threatening emergency if left untreated.

The best way to identify your symptoms is to seek medical help, who can diagnose and treat both hives and angioedema.

If you have hives along with any of the following symptoms:

• Difficulty breathing 
• Difficulty swallowing 
• Feeling faint or lightheaded 

You might have an anaphylaxis reaction, which will require immediate medical care.

Diagnosis of hives 

Your doctor will take a thorough medical history and ask about the onset, and potential triggers in an attempt to find the possible cause of hives. Since there are no specific tests for hives, the diagnosis will depend on your history and a thorough examination of your skin performed by your doctor. 

If your medical history and physical examination of the skin suggest there is an underlying problem, your doctor may suggest you go for further testing such as blood tests and allergy skin tests.

Treatment of hives

The best approach to treat hives is to identify and remove the trigger, however, this is often a very difficult task. Other medications can be used to alleviate the symptoms or prevent new hives formation such as:

• Antihistamines - blocking the effect of histamine can reduce itching and rash (e.g. cetirizine, cimetidine) 
• Corticosteroid - reduces swelling, redness, and itching, usually for short-term control of severe hives (e.g. prednisolone) 
• Antibodies Injection - injectable chemicals that are effective against a difficult-to-treat chronic hives (e.g. omalizumab) 
• Another immunosuppressant - may be required in severe cases for long-term control (e.g. cyclosporine)