Hives, also known as urticaria, are itchy, raised, red or skin-colored welts that appear on the skin. These welts can vary in size and shape, ranging from small spots to larger patches, and often fade within a few hours to a day, although new hives may continue to appear. Hives are a reaction by the body’s immune system, often triggered by allergens, infections, or other factors.
Types of Hives
- Acute Urticaria:
- Lasts less than six weeks.
- Often caused by specific triggers like food, medication, or an infection.
- Chronic Urticaria:
- Persists for more than six weeks.
- Cause may be harder to identify and might be related to an underlying autoimmune condition.
- Physical Urticaria:
- Triggered by physical stimuli, such as:
- Cold (cold urticaria).
- Heat.
- Sunlight (solar urticaria).
- Pressure or friction (dermatographism).
Symptoms
- Raised, itchy welts on the skin.
- Welts may be red, skin-colored, or lighter in the center.
- Welts can appear anywhere on the body, including the face, lips, tongue, throat, or ears.
- Swelling (angioedema) in deeper layers of the skin, often around the eyes, lips, or extremities.
- Welts may change size, shape, or location, and usually resolve without scarring.
Causes
Hives occur when histamine and other chemicals are released from mast cells in the skin, leading to swelling and irritation. Common triggers include:
- Allergens:
- Foods (e.g., nuts, shellfish, eggs, milk).
- Medications (e.g., antibiotics, aspirin, ibuprofen).
- Insect bites or stings.
- Infections:
- Viral infections (e.g., colds, hepatitis, or mononucleosis).
- Bacterial or fungal infections.
- Environmental Factors:
- Temperature extremes.
- Pressure or tight clothing.
- Sunlight.
- Autoimmune Conditions:
- Chronic urticaria may involve the immune system attacking its own tissues.
- Other Factors:
- Stress or anxiety.
- Exercise-induced reactions.
- Hormonal changes.
Diagnosis
- Medical History: Identify triggers, recent medications, or new foods.
- Physical Examination: To check the appearance and distribution of hives.
- Tests (for chronic or unexplained hives):
- Allergy tests (skin prick or blood tests).
- Blood tests to check for autoimmune disorders.
- Physical stimulation tests for cold or pressure-induced hives.
Treatment
- Avoid Triggers:
- Eliminate known allergens or irritants.
- Medications:
- Antihistamines: Reduce itching and swelling (e.g., loratadine, cetirizine, diphenhydramine).
- Corticosteroids: For severe cases, to reduce inflammation.
- Leukotriene Receptor Antagonists: Used for chronic cases unresponsive to antihistamines.
- Epinephrine: For emergency treatment of severe allergic reactions (anaphylaxis).
- Lifestyle Modifications:
- Wear loose-fitting clothing.
- Avoid hot showers or baths.
- Use cool compresses to relieve itching.
- Advanced Treatments (for chronic urticaria):
- Omalizumab (Xolair): A monoclonal antibody approved for chronic idiopathic urticaria.
- Immunosuppressants: For autoimmune-related cases.
Complications
- Severe swelling in the throat or tongue may block the airway, leading to difficulty breathing (anaphylaxis).
- Chronic hives can impact quality of life, causing stress, anxiety, or depression.
Prognosis
- Most cases of acute hives resolve within a few hours to a few days once the trigger is removed or treated.
- Chronic hives may persist for months or years but can often be managed with the appropriate treatment plan.
