Hives (urticaria) and swelling of deep skin tissue (angioedema) cause discomfort, disability and emotional distress to the children who suffer from them. These conditions make the child miserable and the treatment may cause distress as well. Many evaluations and procedures may have to be done to find the cause.
WHAT IS A HIVE?
A hive is a well-defined, raised, itchy area of swelling on the skin. Hives may differ from other skin reactions in a few key ways. The size of the hives can be a fraction of an inch to many inches. Hives almost always itch and they tend to come and go in groups.
Hives typically remain on the skin less than 24 hours. Rarely, the spots will stay for as long as two days. If they last longer, then they are not typical hives. Swelling that lasts longer than two days may be associated with inflammation of blood vessels, or vasculitis. Also, with typical hives, the skin should be clear after the spot disappears. There are more serious variations of hives where there is actual bleeding into the skin. leaving a mark for many days.
FACTS ABOUT HIVES
Chronic hives occur on most days for eight or more weeks. Episodes lasting less than eight weeks are acute hives. When chronic hives is the diagnosis, it should be reassuring that in half of affected children, the illness goes away in about a year.
About 0.1 percent of the population has hives. It is more common in adults and more common in females. The earliest reported case of hives was in a one-month old infant.
Hives may be accompanied by angioedema (swelling of the deeper tissue of the skin). Angioedema usually does not itch. It is seen more frequently around the eyes, lips, tongue, hands and feet. Children who have hives with angioedema tend not to get better as quickly. It has been reported that 75 percent will continue to swell and have hives for five years.
WHAT CAUSES A HIVE?
The list of causes for hives is very long. The following is a short list of general causes for hives.
Physical hives due to:
Allergic reactions due to:
- Mold spores
Non-allergic reactions due to:
- Food additives
- Idiopathic reasons, when no cause is found
Hives can be caused by a number of mechanisms:
- A classic allergic mechanism involving IgE antibodies
- By activation of a part of the immune system, called a complement
- By direct stimulation of cells
- By alterations of proteins by non-steroidal anti-inflammatory agents (NSAIDs, such as aspirin or ibuprofen)
Often, a food is suspected as the cause of hives. Food may account for only 5 percent of acute hives cases. In these situations, the patient and their family can easily see the cause and effect relation. Foods are a rare cause of chronic hives. Poorly documented studies suggest that caffeine, sulfites, monosodium glutamate (MSG) and nickel may cause hives. Our pediatric allergists use caution regarding food claims and typically do not suggest elimination diets or rotational diets as treatment.
Hives can be caused by an allergen in direct contact with the skin. These spots occur only where the allergen touched the skin.
Infections may cause chronic hives. Most infection types—viral, bacterial, fungal and parasitic—have been associated with hives.
Some suggest dyes, preservatives, antioxidants, flavor enhancers and naturally occurring salicylates (which are aspirin-like natural products in foods) cause hives. These are referred to as pseudo-allergens. They may be the cause, but there are no tests other than a challenge (putting the person with hives into contact with the potential allergen) to verify the cause and effect relationship. Hives caused by these agents are not IgE mediated (meaning they are not the “classic” allergy) and cannot be assessed by skin testing.
A PRACTICAL APPROACH TO EVALUATING HIVES
Gathering a careful history and performing a physical exam is essential and the most effective first step your doctor can take in determining the cause of hives. Any testing done beyond this will be determined by what the history and physical exam reveal. Typically, the initial evaluation is done to be sure nothing else is associated with the occurrence of the hives.
The Choosing Wisely® campaign is an initiative to help physicians and patients engage in conversations to reduce overuse of tests and procedures. The goal is to support physician efforts to help patients make smart and effective choices about their care. They have identified chronic hives as an area of concern where tests and procedures may be overused. There are specific recommendations provided by the Choosing Wisely® campaign and the American Academy of Allergy, Asthma and Immunology for the evaluation of chronic hives.
Skin testing for hives is not very conclusive and should only be performed to support a clinical impression. In only about 9 percent of patients does an allergy test show a cause and that is only in cases where the patient history supported the result.
If lesions are persistent or have color changes, consider consulting a dermatologist.
WHEN TO SEE A SPECIALIST?
Those who have peanut-induced or latex-induced hives should see an allergist. If there is a poor response to treatment or if angioedema (deep layer skin swelling) accompanies the hives, then a visit to an allergist is necessary. If the hives are accompanied by other complaints, then a visit is encouraged. Any child or family member who has concerns and wants a thorough evaluation is welcome in our clinic.
As with all allergic disorders, avoidance is the only sure therapy. If a cause for the hives can be determined, then avoidance can be attempted.
Medications like antihistamines are the most important medications to use for hives. The itch should respond to the medicine, but sometimes the redness will remain. There are many antihistamines to choose from. Some cause drowsiness; others may work better for certain types of hives.
Infrequently, a second antihistamine can be added, which is often an antihistamine used to treat excessive stomach acid. It has been found that some combinations of histamine type 1 and histamine type 2 receptor blockers offer relief. In the most severe cases, steroids may be used for treatment.
Finding the cause of chronic hives (lasting more than 8 weeks) is difficult. With acute hives (lasting less than 8 weeks), families are good at diagnosing the cause because they have typically observed the cause and effect relationship. Evaluations for acute hives usually exclude other disorders associated with hives.
Medications control symptoms, but they are not a cure.