Diagnosis and Assessment of Chronic Spontaneous Urticaria

Initial Evaluation

The American Academy of Allergy, Asthma, and Immunology recommends establishing the diagnosis through specific questioning about wheal characteristics and duration 1
The European Academy of Allergology and Clinical Immunology suggests asking about the duration of individual wheals to differentiate between chronic spontaneous urticaria (CSU) and urticarial vasculitis, with wheals lasting >24 hours indicating the latter 1
The American College of Allergy, Asthma, and Immunology recommends inquiring about the ability to induce wheals, as a positive response indicates chronic inducible urticaria rather than CSU 2, 1
Documenting the frequency and timing of wheal occurrence and pruritus severity is essential, according to the Journal of Allergy and Clinical Immunology 3
Assessing the presence of angioedema and determining if swelling occurs with or without wheals is crucial, as stated by the Journal of Allergy and Clinical Immunology 3, 4

The American Academy of Dermatology recommends documenting wheal characteristics, such as size, distribution, color, and confluence, to aid in diagnosis 3
Photographing lesions is essential for visual documentation and diagnosis confirmation, according to the Journal of Allergy and Clinical Immunology 7
Dermatographism testing can help assess for physical urticaria, as suggested by the Journal of Allergy and Clinical Immunology 1
The European Academy of Allergology and Clinical Immunology recommends observing individual wheals to confirm they resolve within 24 hours 1
Basic laboratory tests, including complete blood count with differential, C-reactive protein, and total IgE level, are necessary for all patients, as stated by the Journal of Allergy and Clinical Immunology 7

The American College of Allergy, Asthma, and Immunology recommends using validated scoring tools, such as the 7-Day Urticaria Activity Score (UAS7), to establish baseline severity and guide treatment decisions 3, 7
The UAS7 score ranges from 0 to 42, with higher scores indicating greater disease activity, as described by the Journal of Allergy and Clinical Immunology 3, 4
The Urticaria Control Test (UCT) is used to assess disease control, with a score ≥12 indicating well-controlled disease, according to the Journal of Allergy and Clinical Immunology 8
The Angioedema Control Test (AECT) is used to assess angioedema control, with a cutoff of 10 points indicating well-controlled disease, as stated by the Journal of Allergy and Clinical Immunology 7

The American Academy of Allergy, Asthma, and Immunology recommends ruling out urticarial vasculitis, hereditary or acquired angioedema, ACE inhibitor-induced angioedema, and autoinflammatory diseases, such as Schnitzler syndrome and cryopyrin-associated periodic syndromes, through diagnostic tests and clinical evaluation 2, 1, 5, 6
The European Academy of Allergology and Clinical Immunology suggests considering chronic inducible urticaria and performing standardized provocation testing according to international consensus recommendations 2, 1

The American College of Allergy, Asthma, and Immunology recommends second-generation H1 antihistamines at standard doses as first-line treatment, with approximately 40% of patients achieving partial or complete response 5
Updosing second-generation H1 antihistamines up to 4 times standard daily dose is recommended for inadequate response, according to the Journal of Allergy and Clinical Immunology 5
Omalizumab 300mg subcutaneously every 4 weeks is recommended as third-line treatment for inadequate response to high-dose antihistamines, with at least 30% of patients having insufficient response, especially those with IgG-mediated autoimmune urticaria 5
Cyclosporine (up to 5mg/kg body weight) is recommended as fourth-line treatment for omalizumab failure, improving symptoms in 54-73% of patients, especially those with autoimmune CSU, as stated by the Journal of Allergy and Clinical Immunology 8