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Chronic urticaria: Clinical manifestations, diagnosis, pathogenesis, and natural history

Sarbjit Saini, MD
Section Editors
Bruce S Bochner, MD
Jeffrey Callen, MD, FACP, FAAD
Deputy Editor
Anna M Feldweg, MD


Chronic urticaria (CU) is defined by the presence of urticaria (hives), on most days of the week, for a period of six weeks or longer. About 40 percent of patients with CU have accompanying episodes of angioedema [1]. No external allergic cause or contributing disease process can be identified in 80 to 90 percent of adults and children with CU [2-4]. There are several theories regarding the pathogenesis of idiopathic CU, none of which have been conclusively established. CU is a self-limited disorder in most patients, although the average duration of disease is two to five years.

The clinical manifestations, epidemiology, diagnosis, theories of pathogenesis, and natural history of CU will be reviewed here. The management of CU is discussed separately. (See "Chronic urticaria: Standard management and patient education" and "Chronic urticaria: Treatment of refractory symptoms".)


In this review, the term "chronic urticaria" (CU) refers to patients with isolated chronic idiopathic urticaria (CIU), as well as those with both urticaria and angioedema.

Chronic urticaria and chronic idiopathic urticaria — The terms "chronic urticaria" and "chronic idiopathic urticaria" are used interchangeably in this review and in the medical literature. These terms refer to CU in which appearance of lesions is not triggered by consistent or identifiable factors. However, physical urticaria syndromes are variably included in CU. Physical urticarias are disorders in which urticaria is induced by one or more environmental stimuli, such as heat, cold, pressure applied to the skin, exercise, water, vibration, and sunlight. The inclusion of physical urticaria in the definition of CU is based upon the observation that some patients with CU have symptoms triggered by a physical stimulus on some occasions, while most of the symptoms are spontaneous. (See "Physical urticarias" and "Cold urticaria".)

Chronic spontaneous urticaria — The term "chronic spontaneous urticaria" (CSU) is increasingly used instead of CU [5]. This term refers to CU in which appearance of lesions is not triggered by consistent or identifiable factors, and it specifically excludes the physical urticaria syndromes.


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  1. Kaplan AP. Chronic urticaria: pathogenesis and treatment. J Allergy Clin Immunol 2004; 114:465.
  2. Sheikh J. Autoantibodies to the high-affinity IgE receptor in chronic urticaria: how important are they? Curr Opin Allergy Clin Immunol 2005; 5:403.
  3. Harris A, Twarog FJ, Geha RS. Chronic urticaria in childhood: natural course and etiology. Ann Allergy 1983; 51:161.
  4. Kulthanan K, Jiamton S, Thumpimukvatana N, Pinkaew S. Chronic idiopathic urticaria: prevalence and clinical course. J Dermatol 2007; 34:294.
  5. Zuberbier T, Asero R, Bindslev-Jensen C, et al. EAACI/GA(2)LEN/EDF/WAO guideline: definition, classification and diagnosis of urticaria. Allergy 2009; 64:1417.
  6. Greaves M. Chronic urticaria. J Allergy Clin Immunol 2000; 105:664.
  7. Gaig P, Olona M, Muñoz Lejarazu D, et al. Epidemiology of urticaria in Spain. J Investig Allergol Clin Immunol 2004; 14:214.
  8. Confino-Cohen R, Chodick G, Shalev V, et al. Chronic urticaria and autoimmunity: associations found in a large population study. J Allergy Clin Immunol 2012; 129:1307.
  9. Najib U, Bajwa ZH, Ostro MG, Sheikh J. A retrospective review of clinical presentation, thyroid autoimmunity, laboratory characteristics, and therapies used in patients with chronic idiopathic urticaria. Ann Allergy Asthma Immunol 2009; 103:496.
  10. Ferrer M. Epidemiology, healthcare, resources, use and clinical features of different types of urticaria. Alergológica 2005. J Investig Allergol Clin Immunol 2009; 19 Suppl 2:21.
  11. Champion RH, Roberts SO, Carpenter RG, Roger JH. Urticaria and angio-oedema. A review of 554 patients. Br J Dermatol 1969; 81:588.
  12. Hellgren L. The prevalence of urticaria in the total population. Acta Allergol 1972; 27:236.
  13. Juhlin L. Recurrent urticaria: clinical investigation of 330 patients. Br J Dermatol 1981; 104:369.
  14. Buss YA, Garrelfs UC, Sticherling M. Chronic urticaria--which clinical parameters are pathogenetically relevant? A retrospective investigation of 339 patients. J Dtsch Dermatol Ges 2007; 5:22.
  15. Grattan CE. Aspirin sensitivity and urticaria. Clin Exp Dermatol 2003; 28:123.
  16. Hunkin V, Chung MC. Chronic idiopathic urticaria, psychological co-morbidity and posttraumatic stress: the impact of alexithymia and repression. Psychiatr Q 2012; 83:431.
  17. Staubach P, Dechene M, Metz M, et al. High prevalence of mental disorders and emotional distress in patients with chronic spontaneous urticaria. Acta Derm Venereol 2011; 91:557.
  18. Chung MC, Symons C, Gilliam J, Kaminski ER. The relationship between posttraumatic stress disorder, psychiatric comorbidity, and personality traits among patients with chronic idiopathic urticaria. Compr Psychiatry 2010; 51:55.
  19. Malhotra SK, Mehta V. Role of stressful life events in induction or exacerbation of psoriasis and chronic urticaria. Indian J Dermatol Venereol Leprol 2008; 74:594.
  20. Kimyai-Asadi A, Usman A. The role of psychological stress in skin disease. J Cutan Med Surg 2001; 5:140.
  21. Ozkan M, Oflaz SB, Kocaman N, et al. Psychiatric morbidity and quality of life in patients with chronic idiopathic urticaria. Ann Allergy Asthma Immunol 2007; 99:29.
  22. Chung MC, Symons C, Gilliam J, Kaminski ER. Stress, psychiatric co-morbidity and coping in patients with chronic idiopathic urticaria. Psychol Health 2010; 25:477.
  23. Hergüner S, Kiliç G, Karakoç S, et al. Levels of depression, anxiety and behavioural problems and frequency of psychiatric disorders in children with chronic idiopathic urticaria. Br J Dermatol 2011; 164:1342.
  24. Ben-Shoshan M, Blinderman I, Raz A. Psychosocial factors and chronic spontaneous urticaria: a systematic review. Allergy 2013; 68:131.
  25. Kozel MM, Bossuyt PM, Mekkes JR, Bos JD. Laboratory tests and identified diagnoses in patients with physical and chronic urticaria and angioedema: A systematic review. J Am Acad Dermatol 2003; 48:409.
  26. Leznoff A, Sussman GL. Syndrome of idiopathic chronic urticaria and angioedema with thyroid autoimmunity: a study of 90 patients. J Allergy Clin Immunol 1989; 84:66.
  27. Dreskin SC, Andrews KY. The thyroid and urticaria. Curr Opin Allergy Clin Immunol 2005; 5:408.
  28. Caffarelli C, Cuomo B, Cardinale F, et al. Aetiological factors associated with chronic urticaria in children: a systematic review. Acta Derm Venereol 2013; 93:268.
  29. Leznoff A, Josse RG, Denburg J, Dolovich J. Association of chronic urticaria and angioedema with thyroid autoimmunity. Arch Dermatol 1983; 119:636.
  30. Kaplan AP, Finn A. Autoimmunity and the etiology of chronic urticaria. Can J Allergy Clin Immunol 1999; 4:286.
  31. Kikuchi Y, Fann T, Kaplan AP. Antithyroid antibodies in chronic urticaria and angioedema. J Allergy Clin Immunol 2003; 112:218.
  32. Zhang Y, Morita E, Matsuo H, et al. Urticarial erythema associated with IgA myeloma. J Dermatol 2004; 31:661.
  33. Calvo-Romero JM. Diffuse large B cell lymphoma in a patient with hypocomplementemic urticarial vasculitis. J Postgrad Med 2003; 49:252.
  34. Powell RJ, Du Toit GL, Siddique N, et al. BSACI guidelines for the management of chronic urticaria and angio-oedema. Clin Exp Allergy 2007; 37:631.
  35. Joint Task Force on Practice Parameters. The diagnosis and management of urticaria: a practice parameter part I: acute urticaria/angioedema part II: chronic urticaria/angioedema. Joint Task Force on Practice Parameters. Ann Allergy Asthma Immunol 2000; 85:521.
  36. Tedeschi A, Girolomoni G, Asero R, AAITO Committee for Chronic Urticaria and Pruritus Guidelines. AAITO Position paper. Chronic urticaria: diagnostic workup and treatment. Eur Ann Allergy Clin Immunol 2007; 39:225.
  37. Lindelöf B, Sigurgeirsson B, Wahlgren CF, Eklund G. Chronic urticaria and cancer: an epidemiological study of 1155 patients. Br J Dermatol 1990; 123:453.
  38. Chen YJ, Wu CY, Shen JL, et al. Cancer risk in patients with chronic urticaria: a population-based cohort study. Arch Dermatol 2012; 148:103.
  39. Charlesworth EN. The spectrum of urticaria: All that urticates may not be urticaria. Immunol Allergy Clin North Am 1995; 15:641.
  40. Beltrani VS. Urticaria and angioedema. Dermatol Clin 1996; 14:171.
  41. Charlesworth EN. Urticaria and angioedema: a clinical spectrum. Ann Allergy Asthma Immunol 1996; 76:484.
  42. Beltrani VS. Urticaria: reassessed. Allergy Asthma Proc 2004; 25:143.
  43. deShazo RD, Kemp SF. Allergic reactions to drugs and biologic agents. JAMA 1997; 278:1895.
  44. Namazy JA, Simon RA. Sensitivity to nonsteroidal anti-inflammatory drugs. Ann Allergy Asthma Immunol 2002; 89:542.
  45. Ferrer M, Nakazawa K, Kaplan AP. Complement dependence of histamine release in chronic urticaria. J Allergy Clin Immunol 1999; 104:169.
  46. Laman SD, Provost TT. Cutaneous manifestations of lupus erythematosus. Rheum Dis Clin North Am 1994; 20:195.
  47. Zuberbier T, Asero R, Bindslev-Jensen C, et al. EAACI/GA(2)LEN/EDF/WAO guideline: management of urticaria. Allergy 2009; 64:1427.
  48. Kozel MM, Mekkes JR, Bossuyt PM, Bos JD. The effectiveness of a history-based diagnostic approach in chronic urticaria and angioedema. Arch Dermatol 1998; 134:1575.
  49. Jacobson KW, Branch LB, Nelson HS. Laboratory tests in chronic urticaria. JAMA 1980; 243:1644.
  50. Lang DM. Evidence-based diagnosis and treatment of chronic urticaria/angioedema. Allergy Asthma Proc 2014; 35:10.
  51. Bernstein JA, Lang DM, Khan DA, et al. The diagnosis and management of acute and chronic urticaria: 2014 update. J Allergy Clin Immunol 2014; 133:1270.
  52. Maurer M, Magerl M, Metz M, Zuberbier T. Revisions to the international guidelines on the diagnosis and therapy of chronic urticaria. J Dtsch Dermatol Ges 2013; 11:971.
  53. Hide M, Hiragun T, Japanese Dermatological Association. Japanese guidelines for diagnosis and treatment of urticaria in comparison with other countries. Allergol Int 2012; 61:517.
  54. Zuberbier T, Aberer W, Asero R, et al. The EAACI/GA(2) LEN/EDF/WAO Guideline for the definition, classification, diagnosis, and management of urticaria: the 2013 revision and update. Allergy 2014; 69:868.
  55. Kaplan AP. Clinical practice. Chronic urticaria and angioedema. N Engl J Med 2002; 346:175.
  56. Jirapongsananuruk O, Pongpreuksa S, Sangacharoenkit P, et al. Identification of the etiologies of chronic urticaria in children: a prospective study of 94 patients. Pediatr Allergy Immunol 2010; 21:508.
  57. Zuberbier T. Urticaria. Allergy 2003; 58:1224.
  58. Llamas-Velasco M, Fraga J, Requena L, et al. [Neutrophilic urticaria or urticaria with predominantly neutrophilic inflammatory infiltrate: study of its clinical and histopathologic characteristics and its possible association with rheumatic disease]. Actas Dermosifiliogr 2012; 103:511.
  59. Vonakis BM, Saini SS. New concepts in chronic urticaria. Curr Opin Immunol 2008; 20:709.
  60. Konstantinou GN, Asero R, Ferrer M, et al. EAACI taskforce position paper: evidence for autoimmune urticaria and proposal for defining diagnostic criteria. Allergy 2013; 68:27.
  61. Grattan CE, Wallington TB, Warin RP, et al. A serological mediator in chronic idiopathic urticaria--a clinical, immunological and histological evaluation. Br J Dermatol 1986; 114:583.
  62. Grattan CE, Hamon CG, Cowan MA, Leeming RJ. Preliminary identification of a low molecular weight serological mediator in chronic idiopathic urticaria. Br J Dermatol 1988; 119:179.
  63. Sabroe RA, Grattan CE, Francis DM, et al. The autologous serum skin test: a screening test for autoantibodies in chronic idiopathic urticaria. Br J Dermatol 1999; 140:446.
  64. Mari A. Allergy-like asthma and rhinitis. A cross-sectional survey of a respiratory cohort and a diagnostic approach using the autologous serum skin test. Int Arch Allergy Immunol 2004; 133:29.
  65. Guttman-Yassky E, Bergman R, Maor C, et al. The autologous serum skin test in a cohort of chronic idiopathic urticaria patients compared to respiratory allergy patients and healthy individuals. J Eur Acad Dermatol Venereol 2007; 21:35.
  66. Taskapan O, Kutlu A, Karabudak O. Evaluation of autologous serum skin test results in patients with chronic idiopathic urticaria, allergic/non-allergic asthma or rhinitis and healthy people. Clin Exp Dermatol 2008; 33:754.
  67. Fagiolo U, Kricek F, Ruf C, et al. Effects of complement inactivation and IgG depletion on skin reactivity to autologous serum in chronic idiopathic urticaria. J Allergy Clin Immunol 2000; 106:567.
  68. Fusari A, Colangelo C, Bonifazi F, Antonicelli L. The autologous serum skin test in the follow-up of patients with chronic urticaria. Allergy 2005; 60:256.
  69. Perez A, Woods A, Grattan CE. Methotrexate: a useful steroid-sparing agent in recalcitrant chronic urticaria. Br J Dermatol 2010; 162:191.
  70. Lapolla W, Desai N, English JC 3rd. Clinical utility of testing for autoimmunity in chronic idiopathic urticaria. J Am Acad Dermatol 2012; 66:e83.
  71. Gruber BL, Baeza ML, Marchese MJ, et al. Prevalence and functional role of anti-IgE autoantibodies in urticarial syndromes. J Invest Dermatol 1988; 90:213.
  72. Sabroe RA, Greaves MW. Chronic idiopathic urticaria with functional autoantibodies: 12 years on. Br J Dermatol 2006; 154:813.
  73. Tong LJ, Balakrishnan G, Kochan JP, et al. Assessment of autoimmunity in patients with chronic urticaria. J Allergy Clin Immunol 1997; 99:461.
  74. Hide M, Francis DM, Grattan CE, et al. Autoantibodies against the high-affinity IgE receptor as a cause of histamine release in chronic urticaria. N Engl J Med 1993; 328:1599.
  75. Niimi N, Francis DM, Kermani F, et al. Dermal mast cell activation by autoantibodies against the high affinity IgE receptor in chronic urticaria. J Invest Dermatol 1996; 106:1001.
  76. Fiebiger E, Maurer D, Holub H, et al. Serum IgG autoantibodies directed against the alpha chain of Fc epsilon RI: a selective marker and pathogenetic factor for a distinct subset of chronic urticaria patients? J Clin Invest 1995; 96:2606.
  77. Brunetti L, Francavilla R, Miniello VL, et al. High prevalence of autoimmune urticaria in children with chronic urticaria. J Allergy Clin Immunol 2004; 114:922.
  78. Fiebiger E, Hammerschmid F, Stingl G, Maurer D. Anti-FcepsilonRIalpha autoantibodies in autoimmune-mediated disorders. Identification of a structure-function relationship. J Clin Invest 1998; 101:243.
  79. Soundararajan S, Kikuchi Y, Joseph K, Kaplan AP. Functional assessment of pathogenic IgG subclasses in chronic autoimmune urticaria. J Allergy Clin Immunol 2005; 115:815.
  80. Zweiman B, Valenzano M, Atkins PC, et al. Characteristics of histamine-releasing activity in the sera of patients with chronic idiopathic urticaria. J Allergy Clin Immunol 1996; 98:89.
  81. Kikuchi Y, Kaplan AP. Mechanisms of autoimmune activation of basophils in chronic urticaria. J Allergy Clin Immunol 2001; 107:1056.
  82. Kikuchi Y, Kaplan AP. A role for C5a in augmenting IgG-dependent histamine release from basophils in chronic urticaria. J Allergy Clin Immunol 2002; 109:114.
  83. The CU index test is available commercially. www.viracoribt.com (Accessed on April 12, 2012).
  84. Eckman JA, Hamilton RG, Saini SS. Independent evaluation of a commercial test for "autoimmune" urticaria in normal and chronic urticaria subjects. J Invest Dermatol 2009; 129:1584.
  85. Horn MP, Pachlopnik JM, Vogel M, et al. Conditional autoimmunity mediated by human natural anti-Fc(epsilon)RIalpha autoantibodies? FASEB J 2001; 15:2268.
  86. Vasagar K, Vonakis BM, Gober LM, et al. Evidence of in vivo basophil activation in chronic idiopathic urticaria. Clin Exp Allergy 2006; 36:770.
  87. Cho CB, Stutes SA, Altrich ML, et al. Autoantibodies in chronic idiopathic urticaria and nonurticarial systemic autoimmune disorders. Ann Allergy Asthma Immunol 2013; 110:29.
  88. Eckman JA, Hamilton RG, Gober LM, et al. Basophil phenotypes in chronic idiopathic urticaria in relation to disease activity and autoantibodies. J Invest Dermatol 2008; 128:1956.
  89. Bossi F, Frossi B, Radillo O, et al. Mast cells are critically involved in serum-mediated vascular leakage in chronic urticaria beyond high-affinity IgE receptor stimulation. Allergy 2011; 66:1538.
  90. Asero R, Tedeschi A, Riboldi P, Cugno M. Plasma of patients with chronic urticaria shows signs of thrombin generation, and its intradermal injection causes wheal-and-flare reactions much more frequently than autologous serum. J Allergy Clin Immunol 2006; 117:1113.
  91. Asero R, Tedeschi A, Coppola R, et al. Activation of the tissue factor pathway of blood coagulation in patients with chronic urticaria. J Allergy Clin Immunol 2007; 119:705.
  92. Takahagi S, Mihara S, Iwamoto K, et al. Coagulation/fibrinolysis and inflammation markers are associated with disease activity in patients with chronic urticaria. Allergy 2010; 65:649.
  93. Razin E, Marx G. Thrombin-induced degranulation of cultured bone marrow-derived mast cells. J Immunol 1984; 133:3282.
  94. Vliagoftis H. Thrombin induces mast cell adhesion to fibronectin: evidence for involvement of protease-activated receptor-1. J Immunol 2002; 169:4551.
  95. Huber-Lang M, Sarma JV, Zetoune FS, et al. Generation of C5a in the absence of C3: a new complement activation pathway. Nat Med 2006; 12:682.
  96. Takeda T, Sakurai Y, Takahagi S, et al. Increase of coagulation potential in chronic spontaneous urticaria. Allergy 2011; 66:428.
  97. Sajedi V, Movahedi M, Aghamohammadi A, et al. Comparison between sensitivity of autologous skin serum test and autologous plasma skin test in patients with Chronic Idiopathic Urticaria for detection of antibody against IgE or IgE receptor (FcεRIα). Iran J Allergy Asthma Immunol 2011; 10:111.
  98. Kocatürk E, Kavala M, Kural E, et al. Autologous serum skin test vs autologous plasma skin test in patients with chronic urticaria: evaluation of reproducibility, sensitivity and specificity and relationship with disease activity, quality of life and anti-thyroid antibodies. Eur J Dermatol 2011; 21:339.
  99. Yıldız H, Karabudak O, Doğan B, Harmanyeri Y. Evaluation of autologous plasma skin test in patients with chronic idiopathic urticaria. Br J Dermatol 2011; 165:1205.
  100. Parslew R, Pryce D, Ashworth J, Friedmann PS. Warfarin treatment of chronic idiopathic urticaria and angio-oedema. Clin Exp Allergy 2000; 30:1161.
  101. Mahesh PA, Pudupakkam VK, Holla AD, Dande T. Effect of warfarin on chronic idiopathic urticaria. Indian J Dermatol Venereol Leprol 2009; 75:187.
  102. Cugno M, Marzano AV, Asero R, Tedeschi A. Activation of blood coagulation in chronic urticaria: pathophysiological and clinical implications. Intern Emerg Med 2010; 5:97.
  103. Chua SL, Gibbs S. Chronic urticaria responding to subcutaneous heparin sodium. Br J Dermatol 2005; 153:216.
  104. Asero R, Tedeschi A, Cugno M. Heparin and tranexamic Acid therapy may be effective in treatment-resistant chronic urticaria with elevated d-dimer: a pilot study. Int Arch Allergy Immunol 2010; 152:384.
  105. Jacques P, Lavoie A, Bédard PM, et al. Chronic idiopathic urticaria: profiles of skin mast cell histamine release during active disease and remission. J Allergy Clin Immunol 1992; 89:1139.
  106. Cohen RW, Rosenstreich DL. Discrimination between urticaria-prone and other allergic patients by intradermal skin testing with codeine. J Allergy Clin Immunol 1986; 77:802.
  107. Grattan CE, Walpole D, Francis DM, et al. Flow cytometric analysis of basophil numbers in chronic urticaria: basopenia is related to serum histamine releasing activity. Clin Exp Allergy 1997; 27:1417.
  108. Grattan CE, Dawn G, Gibbs S, Francis DM. Blood basophil numbers in chronic ordinary urticaria and healthy controls: diurnal variation, influence of loratadine and prednisolone and relationship to disease activity. Clin Exp Allergy 2003; 33:337.
  109. Caproni M, Giomi B, Volpi W, et al. Chronic idiopathic urticaria: infiltrating cells and related cytokines in autologous serum-induced wheals. Clin Immunol 2005; 114:284.
  110. Ying S, Kikuchi Y, Meng Q, et al. TH1/TH2 cytokines and inflammatory cells in skin biopsy specimens from patients with chronic idiopathic urticaria: comparison with the allergen-induced late-phase cutaneous reaction. J Allergy Clin Immunol 2002; 109:694.
  111. Greaves MW, Plummer VM, McLaughlan P, Stanworth DR. Serum and cell bound IgE in chronic urticaria. Clin Allergy 1974; 4:265.
  112. Kern F, Lichtenstein LM. Defective histamine release in chronic urticaria. J Clin Invest 1976; 57:1369.
  113. Vonakis BM, Vasagar K, Gibbons SP Jr, et al. Basophil FcepsilonRI histamine release parallels expression of Src-homology 2-containing inositol phosphatases in chronic idiopathic urticaria. J Allergy Clin Immunol 2007; 119:441.
  114. Sabroe RA, Francis DM, Barr RM, et al. Anti-Fc(episilon)RI auto antibodies and basophil histamine releasability in chronic idiopathic urticaria. J Allergy Clin Immunol 1998; 102:651.
  115. Liutu M, Kalimo K, Uksila J, Kalimo H. Etiologic aspects of chronic urticaria. Int J Dermatol 1998; 37:515.
  116. Di Campli C, Gasbarrini A, Nucera E, et al. Beneficial effects of Helicobacter pylori eradication on idiopathic chronic urticaria. Dig Dis Sci 1998; 43:1226.
  117. Başkan EB, Türker T, Gülten M, Tunali S. Lack of correlation between Helicobacter pylori infection and autologous serum skin test in chronic idiopathic urticaria. Int J Dermatol 2005; 44:993.
  118. Schnyder B, Helbling A, Pichler WJ. Chronic idiopathic urticaria: natural course and association with Helicobacter pylori infection. Int Arch Allergy Immunol 1999; 119:60.
  119. Wedi B, Raap U, Kapp A. Chronic urticaria and infections. Curr Opin Allergy Clin Immunol 2004; 4:387.
  120. Daoud MS, Gibson LE, Daoud S, el-Azhary RA. Chronic hepatitis C and skin diseases: a review. Mayo Clin Proc 1995; 70:559.
  121. Shakouri A, Compalati E, Lang DM, Khan DA. Effectiveness of Helicobacter pylori eradication in chronic urticaria: evidence-based analysis using the Grading of Recommendations Assessment, Development, and Evaluation system. Curr Opin Allergy Clin Immunol 2010; 10:362.
  122. Nebiolo F, Bergia R, Bommarito L, et al. Effect of arterial hypertension on chronic urticaria duration. Ann Allergy Asthma Immunol 2009; 103:407.
  123. Kozel MM, Mekkes JR, Bossuyt PM, Bos JD. Natural course of physical and chronic urticaria and angioedema in 220 patients. J Am Acad Dermatol 2001; 45:387.
  124. Hiragun M, Hiragun T, Mihara S, et al. Prognosis of chronic spontaneous urticaria in 117 patients not controlled by a standard dose of antihistamine. Allergy 2013; 68:229.
  125. Toubi E, Kessel A, Avshovich N, et al. Clinical and laboratory parameters in predicting chronic urticaria duration: a prospective study of 139 patients. Allergy 2004; 59:869.
  126. van der Valk PG, Moret G, Kiemeney LA. The natural history of chronic urticaria and angioedema in patients visiting a tertiary referral centre. Br J Dermatol 2002; 146:110.