Urticaria: When a Patient Gets Hives

+What is Urticaria
Hives, or urticaria, are pale red swelling of the skin that occur in groups anywhere on the skin and have the potential to be maddening with itching. The wheals may last a few hours and then they may fade usually without a trace, only to be replaced by new lesions, which are in a constant state of flux. Thus, new areas may develop as old areas fade resulting in intense itching and frustration for both the patient and the physician. In rare instances there may be an associated inflammation of the underlying skin blood vessels, in which case the hives may last longer and they may leave reddish stains to the skin.

Hives are very common. In fact, 10-20% of the population will have hives at least once during their lifetime. When hives occur around the lips, around the eyes or the genitals then there may be tremendous swelling and this is referred to as angioedema. Angioedema is associated with hives in 50% of patients and these episodes may be quite frightening to the individual. Rarely, angioedema may even compromise the airway interfering with the ability to easily move air into and out of the lungs thus resulting in a potential for a life threatening event, although this would be uncommon.

Urticaria is one of the most vexing and challenging skin conditions seen by the primary care physician, the allergist or the dermatologist. Perhaps, it is best to think about hives simply as a symptom, much as a fever is a symptom usually with some underlying cause. There are occasions when one' s primary care physician may wish to refer to a specialist for help in diagnosing and treating hives. Allergists are uniquely trained to evaluate patients with hives and they understand the many complexities associated with this disease. It is important to make certain that the American Board of Allergy and Immunology certify the allergist whom you consult with since there are surgeons (ENT surgeons) who sometimes practice " allergy" without the detailed knowledge of allergy & immunology required to be able to adequately evaluate this condition. Dermatology is another specialty which may be called upon to evaluate patients with urticaria and, although they don' t have the expertise in immunology that a board-certified allergist might have, they do understand the cutaneous mechanisms of hives and they are usually willing to work with your allergist is trying to diagnose and treat this condition.

+Acute Hives (Urticaria)
As your allergist attempts to define the cause of your hives, he/she may first wish to determine whether the problem is an acute problem or whether it is a chronic problem. Hives lasting less than six weeks are usually called "acute urticaria". With this type of hives, the cause is more likely to be found and the most common causes for acute hives are food allergy, drugs or infections. Obviously, the most common type of infections are viral and it is not unusual for one to have a viral upper respiratory tract (a "cold", for example) and then one or two weeks after one has recovered then one develops the onset of hives. We believe that the body is able to produce antibodies to the virus during the recovery phase and then those antibodies combine with leftover viral proteins in the blood stream. It is these complexes of viral proteins and antibodies, which then trigger the release of histamine and the onset of hives. Likewise, an individual may develop an immune response to a drug and this may then trigger the events necessary to result in hives. Lastly, foods may also act as an allergen and trigger hives. The medical history, which you provide your physician, is the best clue to the cause of acute hives. For example, if a food is the culprit then there will be a temporal relationship between the onset of hives and the ingestion of the suspect food. Addionally, the onset of hives with any particular hives must be reproducible and will not be responsible to hives only sometimes and then not at other times. Finally, a good physical examination by your physician may help sort out the cause of your hives. There may be physical signs to suggest a specific infectious cause such as viral hepatitis. Or your physician may note that your hives have characteristics, which might suggest that there is inflammation of the blood vessels supplying the skin. Laboratory tests may prove to be a useful adjunct but laboratory tests should never be done without good medical history and physical examination. A quick trip to the emergency department to receive a "steroid shot" for your hives may be a "quick fix" but it may offer very little to sort out the complexities of this disorder and too many corticosteroid injections may have long-term side effects which may be deleterious to your health.

Foods are an obvious candidate to consider as a cause for acute hives. The most common foods that cause hives are nuts, milk, fish, shellfish, eggs, soy and peanuts. Despite a popular conception that strawberries and chocolate are a frequent cause of hives, there is little real scientific evidence to support this common belief. Food allergy in general is much more common in children and this certainly holds true for foods being a cause of hives. It is important to realize that hives may be part of a generalized reaction which has the potential to be life threatening. This generalized reaction is referred to as anaphylaxis and it may occur within minutes of ingesting food to which an individual has developed allergic antibodies. The symptoms of anaphylaxis may include hives all over, difficulty breathing with symptoms that mimic asthma. There may be associated nausea, vomiting and diarrhea. This may eventually result in a drop in blood pressure and a feeling as if one is going to pass out. Hives in this setting represent an emergency and immediate treatment with adrenalin (epinephrine) and antihistamines is imperative. The most common foods associated with anaphylaxis include peanuts, fish, shellfish and nuts and it would be most unusual for one to "out grow" this type of food allergy.

Drugs are another common cause of acute hives. Almost any prescription or over-the-counter (OTC) medication can cause hives. One should not forget to include OTC vitamins, herbs, mineral supplements and cold and sinus medications as potential causes for acute hives. Some of the drugs associated with hives include antibiotics, pain medications, sedatives, tranquilizers and diuretics (fluid pills). Diet supplements, antacids, OTC arthritis medications, laxatives and even eye medications should be considered. In other words, if you have hives it is important to write down all medication and OTC products that you have been taking, and this should be reviewed with your allergist.

+Chronic Urticaria
Chronic urticaria, by definition, are hives which have been present for longer than six weeks and it is this type of hives which may present the greatest challenge to both the patient and the physician. Indeed, we are able to define a specific cause in only about 15% of patients who present with chronic hives and this type of urticaria is referred to idiopathic urticaria. It is in the understanding of this type of hives that allergists have made the greatest progress in elucidating the mechanisms of hive development. Our current understanding of chronic hives indicates that perhaps 40-50% of patients may have an antibody directed against certain cells, which contain histamine (these cells are called mast cells and basophils). When an antibody activates these cells then they release histamine. The released histamine then contributes to the development of hives. Naturally, a complex sequence of events is cast into play in which inflammatory cells come into the skin. It is this inflammatory aspect of chronic hives, which make the treatment very difficult, even when using very high doses of antihistamines. It is this type of hives in which the patients may benefit the most by consultation with an allergist who understands the complexities of the immune system. As was mentioned previously, hives may simply be a symptom of some underlying medical problem. There is evidence that patients who develop chronic hives may be more prone to the development of autoimmune thyroid disease although there is some debate whether this represents a "cause and effect". Chronic hives may be associated with certain connective tissue diseases such as systemic lupus erythematosus. These complex associations with a multitude of diverse diseases dictate that chronic idiopathic urticaria deserves a referral to an allergist/immunologist.
+Treatment of Hives
Obviously, the first approach is to identify a possible trigger for the hives. A complete medical history and physical examination may give the best clue to identifying the mystical culprit. The culprit may be a drug, it may be that OTC herbal pill recommended by the health food store proprietor or it might even be the very first indication of an underlying infection. Usually, acute hives will respond to the use of antihistamines. We now have several antihistamines which have little or no sedation. This lack of drowsy side effect allows us to use higher doses in order to block the effect of histamine on skin. It should be remembered that OTC antihistamines, such as diphenhidramine (Benedryl), could be just as sedating as alcohol. This may expose one to an increased risk of having an accident when driving a car or operating dangerous equipment. For this reason, consultation by an allergist will allow the development of a treatment program which will be both effective and will be relatively free of side effects. We have discussed a type of hives in which skin inflammation plays a large role. It is these patients which pose the greatest challenge to the treating physician. The allergist who is expert in the treatment of hives may wish to consider medications in addition to simply antihistamines or he/she may wish to choose antihistamines which may have certain anti-inflammatory effects.

The Texas Allergy, Asthma and Immunology Society (TAAIS) is a group of more than 220 board-certified Allergists/Immunologists in Texas.

An Allergist/Immunologist is a physician, usually an Internist or Pediatrician, who has had special training and experience in the field of Allergy and Immunology and who is considered to be an expert in the diagnosis and management of immune system disorders such as asthma, allergic rhinitis (hay fever), eczema, urticaria (hives), drug reactions, food allergies, immune deficiencies, and all general aspects of anaphylaxis.

A Board Certified Allergist/Immunologist is a physician who has passed the certifying examination of the American Board of Allergy and Immunology. A list of Board Certified Allergists can be found here. Those with “ABAI” under Board Certification are Board Certified Allergists/Immunologist.