Our expert, Associate Professor Emek Kocatürk, answers the question of what differential diagnoses to consider when confronted with a patient presenting with symptoms of CSU, explaining how to exclude these through a mixture of clinical and laboratory tests.
Chronic spontaneous urticaria presents with itchy hives which usually last for less than 24 hours and resolve without leaving a mark. The diagnosis of CSU is usually made clinically, however there are other diagnoses to consider in the presence of atypical lesions, accompanying symptoms and resistance to treatment.
The main differential diagnosis is urticarial vasculitis, which presents with hives lasting for more than 24 hours and leaves post-inflammatory hyperpigmentation after resolution. If a patient presents with hives and a sensation of burning or pain rather than itching which resolves in more than 24 hours leaving a mark, then a punch biopsy is warranted. The diagnosis of urticarial vasculitis is made by histopathological examination of the wheal, which shows the presence of leukocytoclastic vasculitis.1
In a patient presenting with wheals without angioedema, and with accompanying fever, joint and muscle pain, auto-inflammatory disorders should be suspected. The lesions typically do not respond to antihistamines and the patient feels unwell. The marked elevation of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and a neutrophilic leukocytosis are characteristic for auto-inflammatory disorders. Histopathological examination of the wheal demonstrates infiltrates rich in neutrophils.
Patients with recurrent angioedema without wheals, who are not on ACE-inhibitors, should be asked for a detailed family history. They should be checked for hereditary bradykinin-mediated angioedema (HAE I-III) and angioedema due to acquired C1-inhibitor (C1-INH) deﬁciency (AAE).2 Normal C4 complement levels, C1-inhibitor protein and function levels, the absence of C1-INH antibodies, or mutations in the C1-INH or factor XII gene rules out bradykinin-related angioedema.
In some instances, chronic inducible urticaria (CINDU) may be confused with CSU. The discriminating question is: “Can you make your wheals appear?”. The answer will distinguish CINDU (‘yes’) from CSU (‘no’). Patients suspected to have CINDU should be investigated for speciﬁc trigger(s) of wheal induction (e.g., skin contact with cold water in cold urticaria; exercise or sauna/hot bath in cholinergic urticaria), and offered provocation testing if possible.3
In the presence of ordinary chronic urticaria, without any indication of other diseases, the EAACI guidelines for urticaria (2013) recommend only limited routine diagnostic testing, including differential blood count and ESR or CRP. 4
Dr Emek Kocatürk received her MD degree from Hacettepe University School of Medicine, Ankara, Turkey in 1999.
Christian Vestergaard, Associate Professor in the Department of Dermatology at the University of Aarhus, Denmark answers the question, 'How should the UAS7 be used in chronic spontaneous urticaria?'.
Werner Aberer, Professor of Dermatology and Chairman at the Department of Dermatology, Medical University of Graz, Austria answers the question 'When a patient has been started on omalizumab, can you stop antihistamine treatment?'.
Karoline Krause, Assistant Professor of Dermatology at the Department of Dermatology and Allergy, Charité – Universitätsmedizin Berlin, Germany, is posed the question: 'Do IgE levels need to be measured before starting a patient with chronic spontaneous urticaria on omalizumab?'.
Doctor Marta Ferrer of Clínica Universidad de Navarra, Pamplona, discusses how pregnancy affects treatment options for CSU, answering the question, 'Can chronic spontaneous urticaria be treated during pregnancy?'.
Professor Ana Giménez-Arnau, Professor of Dermatology at the Hospital del Mar, Universitat Autònoma, Barcelona discusses how to choose a third-line treatment in a patient who has not responded to antihistamine treatment.
Professor Martin Metz of University Hospital Charité, Berlin discusses when to consider withdrawing treatment in those who no longer have symptoms, answering the question 'When should you stop treating a patient with CSU?'.
Associate Professor Christian Vestergaard addresses the role of topical steroids in chronic spontaneous urticaria, answering the question 'Are topical treatments such as topical corticosteroids recommended in chronic spontaneous urticaria?'.
Professor Aberer of the University of Graz answers the question of which antihistamine to choose in a newly diagnosed patient with CSU, discussing the benefits of second-generation antihistamines and dosing strategies.
Associate Professor Emek Kocatürk discusses the investigations that should be carried out when seeing a patient with new onset chronic spontaneous urticaria.
Take a look at some of the frequently asked questions about the low-pseudoallergen diet, answered by our expert Josefine Grünhagen. Including the effects of pre-cooking meals and the use of raising agents in bread and eggs in cakes.
Josefine Grünhagen discusses the use of low-pseudoallergen diets in relation to patients with chronic spontaneous urticaria symptoms.