Some people break out in hives whenever they share a room with a cat. Others find themselves covered in these itchy red bumps when they’re feeling stressed. While stress-induced hives usually resolve on their own, other types of hives require treatment that can range from antihistamines to oral steroids. Most of the time hives are short term, but some people suffer from chronic hives that can last for years, leading to problems such as sleep loss and depression.
Hives are part of an allergic reaction that occurs when a chemical called histamine is released by cells in the body called mast cells. The release of histamine can be triggered in response to a variety of stimuli, including certain foods, medication or even heat or cold. In some cases, chronic hives may be a sign of an underlying disease condition. In others, it can very difficult for an allergist-immunologist to figure out the cause of hives.
Below, Barbara Muller, MD, a professor of clinical medicine in the allergy-immunology Division of the Department of Internal Medicine at University of Iowa Hospitals and Clinics, Iowa City, discusses common causes of hives and treatment approaches for short-term and chronic hives.
What are hives?
Hives are raised, itchy wheal-and-flare reactions on the skin medically referred to as “urticaria.” The lesions look and itch similar to mosquito bites. They can be very small, a few millimeters in size, or become quite large, several centimeters in size, especially with scratching. They often coalesce to involve an entire portion of an extremity or extend to the abdomen or trunk. The itching associated with hives is bothersome and can be intense. If severe, the hive outbreak can include symptoms such as fatigue, chills or joint aches.
Individuals who develop hives may also suffer from a condition called “angioedema” where swelling occurs in the deeper part of the skin. Swelling can be severe and lead to deformity of a portion of the face, lips, around the eyes or genitalia. If swelling occurs in the throat, breathing may be affected and medical attention must be sought immediately.
How long do hives last?
Hives can develop suddenly and last a few hours or days, or continue for weeks or months at a time. Hives lasting less than six weeks are referred to as acute. Outbreaks can also be long-term, or chronic, lasting longer than six weeks. Hives can reoccur often over years.
What causes hives?
Acute cases of hives that come on suddenly and are short-term are generally caused by ingesting a food or medication you are allergic to, or by contact with or exposure to an allergen in your environment.
Basic food allergy is a common trigger of hives. Tree nuts including brazil nuts, walnuts, cashews and almonds or legumes such as peanuts are common causes of allergic reactions. Seafood, particularly shrimp, lobster, crawfish, and mollusks are also commonly reported. Eggs, milk, soy, cheese, wheat, strawberries and tomatoes are all known to cause hives in susceptible individuals.
Preservatives or additives in foods can also cause hives. Rarely, people can be allergic to tartrazine, yellow dye number 5, or other coloring additives found in many processed foods such as candies, puddings, etc. Keeping a diary noting the foods ingested prior to the development of hives can help you figure out which foods you may be allergic to.
Allergic reactions to medications are a commonly reported cause of hives. Penicillin, cephalosporins (semisynthetic penicillins), aspirins, non-steroidal anti-inflammatory drugs, opiates, and muscle relaxants may produce acute reactions in susceptible individuals. If you begin a new medication and develop hives or red blotches on the skin, you should report the reaction to your prescribing physician immediately, before taking another dose.
Various ingredients used in the manufacturing of cosmetics and fragrances can also trigger hives. People who are allergic to bee or wasp venom may develop hives or more serious reactions if stung. It is important to seek medical attention promptly if you suspect you are having an allergic reaction.
What role can the environment have on the development of hives?
Environmental triggers, such as animal dander, dust mites, pollen, mold spores, reactions to chemical irritants or odors, can also cause hives in individuals who are sensitive to these substances.
Some individuals who have “physical urticarias” develop hives in response to various physical stimuli in the environment. This type of hives is usually long lasting and likely to recur. Pressure, vibration, cold, heat, water, exercise, sunlight, temperature changes and other physical stimuli can provoke hives.
Does stress/anxiety cause hives?
Stress, anxiety, excitement and emotional situations can all cause changes in the body’s nervous system and are capable of producing hives in certain individuals. These outbreaks are generally short term and resolve on their own.
When can hives be a sign of underlying disease?
Patients with chronic hives may have underlying disease that has gone undiagnosed. Certain health conditions such as a thyroid disorder, hepatitis, viral infection or even cancer can produce hives. They have also been associated with parasitic, fungal or bacterial infections. Interestingly enough, an increase in hives has been reported in females in the premenstrual period or during the perimenopausal stage of life.
If no allergies or obvious physical triggers are uncovered in the initial clinical investigation, your doctor can perform a basic laboratory evaluation to see if there is an underlying disease.
What are treatment steps for acute hives?
Treatment will depend on the cause and severity of symptoms. Of course, you should avoid contact with the particular substance associated with the development of the hives. Generally speaking, a mild case of a few hives can be controlled rather quickly by taking antihistamines. I would advise keeping the skin moist and trying not to scratch, because this will make the hives worse.
On the other hand, people can have a full-blown acute reaction where they are very sick with a massive breakout of hives on the skin, intense itching, and progressing symptoms including headache, dizziness, vomiting and flu-like symptoms. In some cases, an allergic reaction can develop almost within minutes and that can cause life-threatening symptoms such as breathing difficulties and swelling in the throat. In these cases, medical attention should be sought without delay. They should report to the nearest emergency room immediately. Patients with a history of recurrent serious outbreaks are prescribed an EpiPen, an adrenaline syringe that they keep with them at all times for immediate use when symptoms begin to develop.
How do you treat chronic hives?
It is important to consult a specialist, an allergist or dermatologist, to investigate difficult to control or recurrent hives. Ruling out an underlying medical problem associated with chronic hives is the first step. If there is no known cause, symptoms can be managed with medication. Oftentimes, a variety of medications and dosages or combinations are tried to adequately control outbreaks. Long-acting, non-sedating antihistamines; stomach protection medicines that contain histamine blocker such as Tagamet; and other supplemental medications (for example, certain antidepressants) have all been used to treat hives. If these medications are not successful, oftentimes short-term treatment with oral steroids will control the outbreak.
What about immediate relief of itching?
Topical treatments can be helpful to soothe symptoms. Oatmeal soap sold in pharmacies for irritated skin is helpful in keeping skin moist. Using a good moisturizer will assist in preventing the itch-scratch cycle responsible for development of additional hives. Antihistamines, which are available with and without a prescription, will lessen the itching. Sedating antihistamines may be taken at night to lessen the urge to scratch. If the skin is very irritated, gloves can be worn at night to prevent scratching.