From the Research
The workup for neurogenic urticaria should begin with a thorough clinical history and physical examination to establish the relationship between neurological stimuli and urticarial reactions, as recommended by the most recent guidelines 1. The initial evaluation should focus on identifying potential triggers and underlying conditions that may be contributing to the urticaria.
- Initial testing should include: + Complete blood count + Comprehensive metabolic panel + Thyroid function tests + Erythrocyte sedimentation rate to rule out underlying systemic conditions, as suggested by 2 and 3. Specific testing for neurogenic urticaria involves provocation tests where the suspected neurological trigger (such as stress, temperature changes, or physical exertion) is applied under controlled conditions to observe the urticarial response.
- Skin biopsy may be considered if the diagnosis remains unclear, looking for mast cell degranulation without significant inflammatory infiltrate.
- Autonomic function testing might be warranted in cases with prominent autonomic symptoms. Treatment typically begins with second-generation H1 antihistamines like cetirizine 10mg daily or fexofenadine 180mg daily, which can be increased up to four times the standard dose if needed, as recommended by 1 and 3.
- For refractory cases, adding H2 blockers such as ranitidine 150mg twice daily or leukotriene receptor antagonists like montelukast 10mg daily may help.
- Severe cases might require immunomodulators such as cyclosporine (3-5mg/kg/day) or omalizumab (300mg subcutaneously every 4 weeks), as suggested by 1 and 3. Neurogenic urticaria results from neurogenic inflammation where neuropeptides like substance P and calcitonin gene-related peptide trigger mast cell degranulation, leading to histamine release and subsequent urticarial wheals. The association between chronic urticaria and thyroid pathology, as discussed in 4, highlights the importance of considering thyroid function tests in the initial evaluation. However, the primary focus should remain on identifying and managing the underlying triggers and conditions contributing to the neurogenic urticaria, rather than solely on thyroid pathology.