Hives also called urticaria is a common skin disorder characterized by well defined, raised patches with a red margin that forms on the skin surface. It usually occurs due to allergy to certain foods or medicines. Hives can affect any part of the body but most commonly occur on the arms and legs and are often itchy.
Hives may be of two forms:
- Acute hives – condition lasts for less than 6 weeks.
- Chronic hives – condition lasts for more than 6 weeks.
Hives appear suddenly as a skin rash with smooth, raised reddish bumps called wheals, similar to an insect bite. The rash is very itchy. The redness of the rash seems to disappear when you apply pressure on it. This is referred to as blanching.
In most cases, the exact cause for acute urticaria remains unknown. Some possible causes for the acute form of urticaria are listed below.
- Infections – Fungal or viral infections of organ systems
- Insect bites
- Allergy to certain foods such as shellfish, fish, eggs, cheese, chocolate, nuts, berries, and tomatoes
- Medicines such as penicillins, antihistamines, and non-steroidal anti-inflammatory drugs (NSAIDs),sleeping pills, blood pressure medications
- Environmental factors – pollens, chemicals, plants, animal danders, dust, and molds
- Allergy to latex products
- Exposure to extremes of cold or heat
- Emotional stress
Chronic Urticaria may be caused by all the factors which cause the acute form. In addition, other causes can include autoimmune disorders, emotional stress, heat, exercise, and chronic illnesses such as thyroid diseases, cancer and lupus.
Recurrent urticaria can occur because of chronic sun exposure, exercise and stress.
Your doctor will take a complete medical history and perform a physical examination of the rash. A previous history of allergy will suggest hives. Your doctor may order basic laboratory tests such as complete blood count and erythrocyte sedimentation rate (ESR) to confirm the condition. A punch biopsy will be done if the lesion persists for more than 24 hours accompanied by intense pain and itching.
Medications that your doctor may prescribe include:
- H1-receptor antagonists (antihistamines): Acute forms of urticaria will be treated with H1 antihistamine drugs. Some of the common H1 antihistamines are Hydroxyzine hydrochloride (Atarax®, Vistaril®), Diphenhydramine (Benadryl®, Benylin®, Diphen®).
- H2 antihistamines such as Famotidine (Pepcid®), Ranitidine (Zantac®) Cimetidine (Tagamet®) will be added in persistent cases.
- Chronic forms of urticaria are treated with glucocorticosteroids. A tricyclic antidepressant, doxepin, also helps in persistent cases.
- Skin creams – Doxepin cream 5% (Zonalon®) or capsaicin may also be recommended.
Some of these preventive methods can help prevent the occurrence of hives.
- Avoid taking over-the-counter medication such as cold and sinus tablets and decongestants, medication for headaches, cough medicines, lozenges, mouth washes, laxatives, douches, hemorrhoid medications and suppositories, vaginal suppositories and medications, vitamins and tonic water
- Avoid exposure to allergic substances (medication, food, environmental factors).
- Avoid wearing tight clothes.
- Avoid hot baths or showers.
- Avoid vigorously rubbing your skin with a towel after a bath instead just pat your skin dry.
- Apply moisturizer to your skin frequently to prevent dryness of skin as it often worsens hives.
- Manage physical and emotional stress by relaxation methods and meditation.