Patients who have urticaria (hives) have localized, itchy, pale, pink wheals that can sting, or burn. They can be found singularly as well as in clusters on any area of a patient’s skin; and are caused by an allergic reaction. This is an extremely common condition. Approximately 15 percent of people will experience one or more episodes during their lifetime. Most episodes of hives disappear quickly in a few days to a few weeks. Occasionally, a patient may have them last for many months to years. New hives can develop as old ones fade. The size of hives can vary from as small as a pencil eraser to as large as a dinner plate, and may join to form even larger areas of swelling.
Hives are produced by blood plasma leaking through tiny gaps between the cell lining small blood vessels in the skin. Histamine is a chemical released from cells in the skin called "mast cells" these lay along blood vessels. Allergic reactions, medications, or chemicals in foods may cause hives; sometimes it is impossible to find out the cause. When hives form around the eyes, lips, or genitals, the tissue can swell excessively. While this can be frightening, the swelling typically goes away in less than 24 hours. Severe cases of hives may cause difficulty in breathing or swallowing and emergency room care is required.
generally lasts less than six weeks. An underlying cause can often be identified and eliminated. Some of the most frequent causes of acute urticaria include; drugs, foods, or infections. Other possible cause included cold, internal diseases, insect bites, pressure, or sunlight.
Almost any medication -- prescription or over-the-counter -- can cause hives. Antacids, antibiotics, arthritis medication, diet supplements, diuretics (water pills), eye and eardrops, herbal supplements, laxatives, pain medications, sedatives, tranquilizers, vitamins, vaginal douches, or any other non-prescription item can be a potential cause of urticaria. It is important to inform the dermatologist of ALL prescription and over-the-counter medications being used to help find the cause of the hives.
FOODS The foods that most commonly cause urticaria include: berries, chocolate, eggs, milk, nuts, shellfish, and tomatoes. Fresh foods are responsible for hives more often than cooked foods. Food preservatives and additives may also cause hives. Hives can appear within minutes to several hours after eating.
Many infections can result in the development of urticaria. Viral upper-respiratory tract infections (colds) are a common cause in children. Other viruses, including hepatitis and a number of bacterial and fungal infections, may cause urticaria.
lasts for more than six weeks. The cause of chronic urticaria is more difficult to identify and is found only in a small number of patients. The dermatologist reviews a patient's medical history, asks extensive questions, and conducts a thorough physical examination. Testing, such as a biopsy and blood work may be needed.
Some feel that patient with chronic urticaria may be sensitive to salicylates. This is the active ingredient in aspirin; salicylates are found to some extent in all plant matter (fruits, herbal supplements, veggies, etc.). If you find that taking aspirin makes your hives worse, you may have discovered your cause. This is also true if you cannot tolerate other non-steroidal anti-inflammatory drugs (NSAIDs), such as Ibuprofen since they are cross-reactive with salicylates.
The foods most commonly reported to induce urticaria are berries, cheese, chocolate, eggs, fish, milk, nuts, shellfish, tomatoes, and wheat.
Foods reported to release histamine directly from mast cells are alcohol, chocolate, fish, shellfish, strawberries, tomatoes, pineapple, and uncooked egg whites. Foods reported to be high in histamine are beef sausage, beer, brewer's yeast, chocolate, dry pork sausage, camembert, canned fish, chicken, fermented cheeses (e.g. Brie, Cheddar, Gruyere, Roquefort, and Parmesan), fermented soy products, fermented vegetables (sauerkraut), fin fish, ham, red wine (particularly Chianti), shellfish, spinach, tomato, unpasteurized milk (e.g., cow, goat or human milk). More information on a salicylate-free or histamine restricted diet can be found at: www.chronichives.com
DERMATOGRAPHIC URTICARIA (DERMATOGRAPHISM)
urticaria develops after firmly stroking or scratching the skin, and frequently occurs with other forms of urticaria. It affects 5% of the population. Most people with this condition are otherwise healthy. Dermatographism can last for months and in some cases years.
may be caused by sunlight, heat, cold, water, pressure, vibration, or exercise. Solar urticaria forms within minutes of sun exposure and typically fades within one to two hours. Cold urticaria appears when the skin is warmed after exposure to cold. Urticaria, forms as a response to the water or the cold when swimming, and can produce flushing, wheezing, generalized hives, and fainting.
The best treatment for urticaria is to find and eliminate the cause whenever possible. Antihistamines are prescribed to provide relief and work best if taken on a regular schedule to prevent hives from forming. There are many antihistamines available. No one antihistamine works for everyone. The dermatologist may use combinations to control the urticaria. In severe cases, an injection of epinephrine (adrenalin) may be needed. Cortisone may also bring dramatic relief, but its use must be limited to short periods of time. Less commonly, other systemic medications such as Cyclosporine, Methotrexate or Mycophenolate Mofetil (CellCept) are used.
MORE INFORMATION: www.chronichives.com
We put academic qualifications, many years of combined experience, and training in a variety of special interest areas to work for your healthy, radiant skin. Our providers – Drs. Schachter, Hanna, Curtis, Abdulla, Pollack, and Taradash – welcome new patients for treatment at the Dermatology on Bloor practice on Park Road in Toronto. Our team is here to serve your needs