Urticaria 2

Published on April 27, 2016   25 min

Other Talks in the Series: Skin Biology

The lab evaluation for chronic urticaria is something that we should keep in mind but not always perform. We should keep it focused based on the history and physical exam. For example, you might obtain a CBC with differential or liver function tests if the patient has hepatosplenomegaly or other findings in the history of physical suggestive of lymphoma or other cancers. Eosinophilia might suggest a parasitic infection. And in that case, you might order a stool study for ova and parasites. A TSH and Free T4 could be obtained if the patient has symptoms consistent with hyper or hypothyroidism. And if you note below, I've also listed thyroid antibodies likes TPO or thyroglobulin antibodies, which have been associated with chronic urticaria among other autoimmune and immune complex diseases that are associated with other abnormalities and complements, abnormalities in the ESR or ANA. So if you're suspecting an autoimmune or immune complex disease, those labs are important to obtain. But I wouldn't necessarily order them on regular basis. I would allow the history and physical to guide me in this. The guidelines from the American Academy of Allergy, Asthma, and Immunology, and the EAACA, the European groups also focuses on this that it's important to not obtain these labs on a regular basis, because usually, the history and physical should be able to guide you as to whether these are important to obtain. The last aspect of this slide antibody against the Fc epsilon receptor alpha, which has been found in research to be associated with chronic urticaria in select cases. However, it's not recommended to obtain this lab in routine evaluation of the patient with chronic urticaria, because it doesn't help guide us in the management of the patient. So usually, it's still only obtained for research and interest purposes.
When we're managing and evaluating urticaria, our treatment involves two main lines of approach. One, we should treat the underlying cause and/or remove the triggers that may be causing or worsening the urticaria that the patient is experiencing. And if we're not able to completely resolve the urticaria by removing a particular trigger, we need to manage urticaria by using medication. The following slides are going to go over that in further detail.
For most patients with chronic urticaria, medications are needed to control the symptoms especially when a trigger cannot be identified. Symptomatic management is the most common form of treatment for chronic urticaria. The goal is to suppress the symptoms of urticaria or completely eliminate the symptoms by inhibiting the release and/or the effect of the mast cell mediators or other inflammatory mediators. Antihistamines, antileukotrienes, and systemic corticosteroids are the most common medications that we use in these patients. Other medications I'm going to review with you are immunomodulators, and omalizumab or xolair, which is an anti-IgE antibody.
When evaluating a patient and managing the urticaria, there are two different guidelines that we can use and I want you to realize that these guidelines are very similar. I've listed the European and the American guidelines from 2013 and 2014 respectively. Don't get too bogged down in the details of these guidelines because they can look a little bit busy. I'm going to take you through them and explain to you the major differences. Overall, they're very similar. The first of line therapy for the both is to start with a modern second generation antihistamine, such as cetirizine, fexofenadine, or loratadine. And commonly, our patients have already initiated that. They've already tried starting to take one of these or even two, sometimes, a day. And both guidelines recommend that the second step would be to increase the dose to as many as four tablets of any one of those per day. Note that it's not recommended in the guidelines to mix the medications, and we should choose one of these or the other. So they shouldn't be taking, for example, two tabs of cetirizine and two tabs of loratadine, they should be taking four tabs of one of those. In the AAAAI Guidelines, step two has a few more options than the EAACI step two or in the second line. So the EAACI, the second line is just to increase the dose to four times the typical dose of a second generation antihistamine. Whereas in the AAAAI guidelines, they offer that in addition to adding another second generation antihistamine to the regimen, adding an H2 antagonist, an antileukotriene or even adding a first generation antihistamine, especially at bedtime to help your patient sleep. Step three, for the AAAAI, will be to advance the dose of the stronger antihistamines such as hydroxyzine or diphenhydramine as tolerated. And step four of those same guidelines would be to add on an alternative agent such as Omalizumab, Cyclosporin, other anti-inflammatory or immune modulating medications. And if we go back to the left side, the EAACI guidelines are a little bit more simple and they go straight from the antihistamines to adding Montelukast, or Omalizumab, or other immune modulators. As a clinician, after you've seen several patients with chronic urticaria, it becomes fairly easy to figure out which of these guidelines you like to follow, and also, which one might fit your patient better.