Table 1. Clinical classification of chronic urticaria subtypes (presenting with wheals, angioedema, or both) and recommended diagnostic tests.
Chronic urticaria subtypes | Diagnostic program (suggested based on history) | |
---|---|---|
Spontaneous appearance of wheals, angioedema, or both ≥6 weeks due to known or unknown causes | Chronic spontaneous urticaria | Routine diagnostic tests: differential blood count. liver enzyme. ESR or CRP. |
For identification of underlying causes and for ruling out possible differential diagnosis: (1) test for infection, (2) type I allergy, (3) functional autoantibody, (4) Thyroid disease, (5) ASST, (6) tryptase, (7) Pseudoallergy free diet for 3 weeks, and (8) lesional skin biopsy | ||
Inducible trigger | Inducible urticaria | Routine diagnostic test |
Symptomatic dermographism | Scratching or shear forces on the skin | |
Cold urticaria | Cold provocation test (ice cube) | |
Delayed pressure urticaria | Pressure test (weight bag or special instrument on the arm. | |
Solar urticaria | Sunlight to buttock area | |
Heat urticaria | Metal or glass cylinder filled with hot water on the forearm for 5 minutes | |
Vibratory angioedema | Vortex mixer for 10 minutes - 1,000 rpm on the forearm | |
Cholinergic urticaria | Physical exercise to the point of sweating or hot bath | |
Contact urticaria | Open test with suspected substance | |
Aquagenic urticaria | Attaching compresses with water on the forearm for 20 minutes |
Modified from Zuberbier, et al. Allergy 2014;69:868-871), with permission with Wiley & Sons Inc.
ESR, erythrocyte sedimentation rate: CRP, C-reactive protein: ASST, autologous serum skin test