Chronic urticaria/angioedema and Graves' disease: Coexistence of 2 antireceptor antibody-mediated diseases

An 82-year-old man with recurrent angioedema

Angioedema is a potentially life-threatening swelling condition that can occur either in isolation or in the context of other syndromes, e.g., anaphylaxis. Angioedema is typically asymmetric, lasts for hours to days, is not gravity dependent, and is often nonpitting. Recurrent angioedema is typically associated with histaminergic and bradykinin-mediated causes, some of which can indicate underlying etiologies with high morbidity or mortality. The differential diagnosis for acute angioedema can include anaphylaxis, chronic urticaria with angioedema, medications such as angiotensin-converting-enzyme inhibitors, hereditary C1 esterase inhibitor defects, and acquired defects; however, the cause is often idiopathic, and effective therapy can be elusive. In this article, we described a unique etiology of a case of isolated recurrent angioedema that improved when the possible underlying cause was successfully treated.

Chronic idiopathic urticaria and Graves' disease

Chronic urticaria is a common condition characterized by recurrent episodes of mast cell-driven wheal and flare-type skin reactions lasting for more than 6 weeks. In about 75% of cases, the underlying causes remain unknown, and the term chronic idiopathic urticaria (CIU) is used to emphasize that wheals develop independently of identified external stimuli. Although CIU affects about 1.0% of the general population, its etiopathogenesis is not yet well understood. It is now widely accepted that in many cases CIU should be regarded as an autoimmune disorder caused by circulating and functionally active IgG autoantibodies specific for the IgE receptor (FceRI) present on mast cells and basophils or for IgE itself. The well-known association of CIU with other autoimmune processes/diseases represents further indirect evidence of its autoimmune origin. Autoimmune thyroid diseases, especially autoimmune thyroiditis, represent the most frequently investigated diseases in association with CIU. Here we review this topic with particular regard to the association between Graves' disease and CIU. The possible pathogenetic mechanisms and the clinical implications of such an association are discussed.

Urticaria and thyroid autoimmunity

BACKGROUND

Chronic urticaria is a common clinical condition whose etiology, in about 75% of cases, is unknown and is therefore called chronic idiopathic urticaria (CIU). A link between CIU and autoimmune thyroid diseases was proposed several decades ago. Here we review this topic.

SUMMARY

Several studies have been performed to determine if and to what degree there is an association between CIU and autoimmune thyroid diseases, particularly autoimmune thyroiditis. Many of these studies were not well controlled, however. Approximately one-fourth of CIU patients have serological evidence of thyroid autoimmunity, suggesting that these two disorders are associated. The mechanisms for the apparent association between CIU and serological evidence of thyroid autoimmunity are not clear. There are no data regarding the correlations between CIU and histological features of autoimmune thyroiditis or hypothyroidism. Despite this, there are anecdotal reports regarding L-thyroxine administration in patients with CIU.

CONCLUSIONS

Screening for thyroid autoimmunity is probably useful in patients with CIU. More solid evidence, based on still lacking well-conducted controlled studies, is desirable to determine if there is a therapeutic role for L-thyroxine treatment in ameliorating the skin manifestations of urticaria.

Autoimmunity and mast cell-related diseases

Allergy and autoimmunity are complex inflammatory processes caused by dysregulation of the immune system. There are select situations in which allergy and autoimmunity coexist pathologically. Traditionally considered unrelated, recent evidence suggests unexpected roles for allergic mediators in several autoimmune diseases. This review presents updated evidence for allergic mediators in several autoimmune diseases, as well as autoimmune phenomena in mast cell-related conditions. We will describe the concomitant manifestation of these conditions in patients and in animal models. The involvement of the main effectors of the immune system - mast cells, T lymphocytes, antibodies and cytokines - in both conditions is also discussed.

Mast cells and autoimmunity

Mast cells (MCs) are major effector cells in allergic diseases. Recently, it has become evident that the contribution of MCs extends far beyond their accepted role in allergic disease, and that they play a more extensive role in a variety of non-allergic immune processes such as the innate immunity response. These cells have a key role in both the induction and elicitation of several autoimmune conditions. Targeting MC development, maturation or activation may be of value in future prevention and treatment of autoimmune conditions.

Chronic urticaria and thyroid disease

Because the association of thyroid disease with pruritus and urticaria dates back more than 50 years, many investigators have commented on the possible link between autoimmune thyroid disease and chronic urticaria. This article summarizes an evolving body of literature linking these two conditions and discusses potential mechanisms as to how they concomitantly occur. Treatment options used to manage and control the urticaria are discussed with a focus on how the thyroid gland may have a role in the possible mechanism leading to chronic urticaria in this setting and how thyroid hormone may contribute to resolution of this condition.

Chronic urticaria: a role for newer immunomodulatory drugs?

Chronic urticaria is now recognized as an autoreactive disorder in a substantial fraction of patients. A serologic mediator of whealing has been demonstrated in 50-60% of patients with chronic urticaria, and autoantibodies against the high affinity IgE receptor or IgE have been detected in about half of these patients. The demonstration that chronic urticaria is frequently autoimmune has encouraged a more aggressive therapeutic approach, with the use of immunomodulatory drugs.A step-by-step approach to the management of chronic urticaria is proposed, based on our personal experience and review of current medical literature, identified through Medline research and hand searching in medical journals. The non- or low-sedating H(1) receptor antagonists (antihistamines), such as cetirizine, fexofenadine, loratadine, mizolastine and, more recently, levocetirizine, desloratadine and ebastine, represent the basic therapy for all chronic urticaria patients. Older sedating antihistamines, such as hydroxyzine and diphenhydramine, may be indicated if symptoms are severe, are associated with angioedema, and if the patient is anxious and disturbed at night.Corticosteroid therapy with prednisone or methylprednisolone can be administered for a few days (7-14) if urticarial symptoms are not controlled by antihistamines and a rapid clinical response is needed. In cases of relapse after corticosteroid suspension, leukotriene receptor antagonists, such as montelukast and zafirlukast, should be tried. In our experience, remission of urticarial symptoms can be achieved in 20-50% of chronic urticaria patients unresponsive to antihistamines alone. When urticaria is unremitting and is not controlled by combined therapy with antihistamines and leukotriene receptor antagonists, prolonged corticosteroid therapy may be needed. Long-term corticosteroid therapy should be administered at the lowest dose able to control urticarial symptoms, in order to minimize adverse effects. In a few patients, however, high-dose corticosteroid therapy may have to be administered for long periods. In these patients, immunosuppressive treatment with low-dose cyclosporine can be started. This type of treatment has a corticosteroid-sparing effect and is also generally effective in patients with severe, unremitting urticaria, but requires careful monitoring of cyclosporine plasma concentration and possible adverse effects. Other immunomodulating drugs that have been tried in chronic urticaria patients include hydroxychloroquine, dapsone, sulfasalazine and methotrexate, but their efficacy has not been proven in large controlled studies. Warfarin therapy may also be considered in some patients with chronic urticaria and angioedema unresponsive to antihistamines.

Advances in allergic skin diseases

During the past year there have been significant advances in our understanding of the mechanisms underlying allergic skin diseases. This article reviews some of these advances in atopic dermatitis and urticaria. The introduction of a new class of topical anti-inflammatory medications, topical calcineurin inhibitors, has significantly increased our treatment options and led to a rethinking of potential management approaches in atopic dermatitis.

Chronic urticaria and autoimmune thyroid disease: is there a link?

Chronic idiopathic urticaria (CIU) is a common and frustrating disorder. A subset of patients with CIU has been classified as autoimmune on the basis of two main findings: association with thyroid autoimmunity and anti-IgE and/or anti-IgE receptor antibodies. There is growing evidence that some cases of CIU are associated with thyroid autoimmunity. Patients with CIU have an increased frequency of Hashimoto thyroiditis with the presence of antibodies to thyroglobulin or a microsomal-derived antigen (peroxidase), even in euthyroid patients. No broad non-specific autoimmunity is present. Antibodies reactive with Fc(epsilon)RI, the high-affinity IgE receptor are found in sera of 10-40% of patients with CIU. A smaller subset of patients with CIU lack anti-Fc(epsilon)RI antibodies and have anti-IgE antibodies that cross-link Fc(epsilon)RIs occupied by IgE. There are a minority of CIU patients that lack such antibodies, but can degranulate basophils by a serum factor that has not yet been determined. Most patients with anti-IgE antibodies have an IgG antibody directed against the 34 kd alpha subunit of the IgE receptor. There are no data to suggest that any of the anti thyroid antibodies is pathogenic in terms of CIU, and most likely these are associated, parallel, autoimmune events. Screening for thyroid autoimmunity and function is advisable in all patients with CIU for the early identification of patients requiring either treatment of underlying thyroid dysfunction or follow-up.