- Allergens: Foods (e.g., peanuts, shellfish, eggs, milk), medications (e.g., penicillin, aspirin), insect stings, latex.
- Physical stimuli: Pressure, cold, heat, sunlight, vibration, exercise. This is known as physical urticaria.
- Medications: Prescription and over-the-counter drugs.
- Infections: Viral, bacterial, or fungal infections.
- Insect bites and stings.
- Contact with certain substances: Plants (e.g., poison ivy), chemicals.
- Stress.
- Autoimmune conditions.
- In some cases, the cause of hives cannot be identified (idiopathic urticaria).
- Be itchy (pruritic), sometimes intensely so.
- Vary in size, from small spots to large patches.
- Appear anywhere on the body, including the face, lips, tongue, throat, and ears.
- Change shape, move around, and disappear within hours, only to reappear elsewhere.
- Sometimes join together to form larger raised areas.
- Be accompanied by angioedema, which is swelling in the deeper layers of the skin, often around the eyes, lips, or genitals.
- When the hives started and how long they last.
- Possible triggers, such as foods, medications, or environmental exposures.
- Other symptoms you may have.
- Allergy testing: Skin prick tests or blood tests to identify specific allergens.
- Blood tests: To check for underlying medical conditions.
- Skin biopsy: Rarely needed, but may be done to rule out other skin conditions.
- Provocation testing: For physical urticaria, this involves exposing the skin to suspected physical triggers (e.g., applying pressure, ice).
- Avoidance of triggers: Identifying and avoiding known triggers is crucial.
- Medications:
- Antihistamines: These are the first-line treatment for hives and work by blocking histamine release. Non-sedating antihistamines are usually preferred for daytime use.
- H2 blockers (histamine H2 receptor antagonists): May be used in combination with H1 antihistamines, particularly for chronic hives.
- Corticosteroids (oral or topical): May be prescribed for severe acute hives to reduce inflammation, but are not typically used long-term due to potential side effects.
- Leukotriene receptor antagonists: Can be helpful in some cases, especially when asthma or allergic rhinitis is also present.
- Omalizumab: An injectable medication that targets IgE antibodies and is used for chronic spontaneous urticaria that doesn't respond to antihistamines.
- Cyclosporine and other immunosuppressants: May be used for severe chronic urticaria that is resistant to other treatments.
- Cool compresses or showers: Can help soothe itchy skin.
- Loose-fitting clothing: Avoid tight or irritating clothing.
- Keeping a food and symptom diary to track potential food allergies.
- Informing healthcare providers about any medication allergies.
- Avoiding known physical triggers if you have physical urticaria.
- Managing stress.