Photo Credit: Wisely
Researchers recently published an updated clinical algorithm to support chronic inducible urticaria diagnosis, assessment, and management.
Between 20% and 30% of chronic urticaria cases are likely chronic inducible urticaria (CIndU), which is characterized by pruritic wheal formation and/or angioedema in response to specific triggers. Triggers can include exposure to cold and heat, solar radiation, water, and other physical and nonphysical stimuli.
A team of experts from Charité – Universitätsmedizin Berlin and the Fraunhofer Institute for Translational Medicine and Pharmacology ITMP in Berlin, Germany, recently published updated algorithms for diagnosing and treating CIndU in the journal Allergy.
According to the article, the diagnosis of CIndU is based on patient history and provocation testing. Clinicians should ask patients if they can provoke their wheals and, if so, how. The diagnosis should then be confirmed using provocation testing with validated tools.
“Provocation testing serves the confirmation of relevant triggers and the assessment of trigger thresholds, which is important for measuring skin susceptibility to trigger-induced whealing as well as monitoring of treatment response,” wrote corresponding author Marcus Maurer, MD, and coauthors.
Patients should stop taking antihistamines at least 3 days and glucocorticosteroids at least 7 days before provocation testing. Skin sites affected by urticaria in the preceding 24 hours should not be tested because they may be refractory to whealing.
If provocation testing does not induce wheals, clinicians should ask patients to describe previous triggers that caused whealing and encourage them to take photos if whealing occurs again. Provocation testing should be repeated and guided by patient input on trigger strength, exposure, or other factors if the history, photos, or reassessment suggests CIndU.
“CIndU can be challenging to manage and hard to treat,” the authors wrote, “and it often is.”
Although avoiding triggers used to be a big part of management, it is often difficult for patients, and newer treatment approaches instead focus on protection from trigger-induced whealing until spontaneous remission occurs. The article advises a “three M” approach to management: measure, mitigate, and medicate. Measure the trigger threshold, disease activity, and impact; mitigate triggers; and medicate accordingly.
