From the Guidelines
Stimulants can trigger or worsen urticaria by activating mast cells in the skin, leading to the release of histamine and other inflammatory mediators, as supported by the guidelines for evaluation and management of urticaria in adults and children 1. The mechanism of action of urticaria induced by stimulants involves the stimulant either directly activating mast cells or lowering the threshold for mast cell degranulation. When activated, mast cells release histamine, which causes local vasodilation and increased vascular permeability, resulting in the formation of wheals and surrounding erythema. Some key points to consider in the management of urticaria triggered by stimulants include:
- Identifying and avoiding specific triggers
- Using antihistamines as prescribed by a healthcare provider, with options including cetirizine, desloratadine, fexofenadine, levocetirizine, loratadine, and mizolastine 1
- Considering lifestyle modifications to reduce overall stress and inflammation in the body
- Being aware of the potential for immunomodulating therapies, such as ciclosporin, tacrolimus, and mycophenolate mofetil, in severe cases of chronic autoimmune urticaria 1
- Recognizing the different clinical classifications of urticaria, including ordinary urticaria, physical urticarias, and autoinflammatory syndromes, to guide diagnosis and treatment 1
From the Research
Mechanism of Action of Urticaria Induced by Stimulants
- The exact mechanism of action of urticaria induced by stimulants is not clearly understood from the provided studies 2, 3, 4, 5, 6.
- However, it is known that physical urticarias, which include urticarias induced by external physical stimuli, are present in up to 5% of the general population and in 10 to 50% of patients with chronic urticaria 4.
- The diagnosis of physical urticarias is established through specific provocation tests, and management encompasses avoidance measures, pharmacologic therapy with nonsedating antihistamines, and alternative medications in refractory cases 4, 5.
- Cholinergic urticaria, a type of physical urticaria, is diagnosed based on the patient's history and provocation tests, including trigger threshold testing where possible 5.
- Treatment of urticaria induced by stimulants is mainly symptomatic, and many patients benefit from avoiding eliciting triggers, and desensitization to these triggers can be helpful in some physical urticarias and in cholinergic urticaria 5.
Urticaria Induced by Specific Stimulants
- NSAID-sensitive antihistamine-induced urticaria/angioedema is a possible new subset of antihistamine urticaria, where patients experience urticaria and angioedema after oral antihistamine administration 6.
- The study suggests that some patients may have a sensitivity to certain antihistamines, which can trigger urticaria and angioedema 6.
- However, the exact mechanism of action of this subset of urticaria is not clearly understood and requires further research 6.