Centre of Evidence of Dermatology Best practice guidelines

Guidelines chronic spontaneous urticaria Updated on december 2019


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Chronic spontaneous urticaria and diet

Back to decision-making tree Print last updated on 18/09/2020

Patient picture


Previous treatments

He has taken: desloratadine, then levocetirizine at conventional doses (MA dose, 1 tablet/day), and for the past week mizolastine 1 tablet/day and ranitidine 1 tablet/day, without any improvement.

Other elements

What do you suggest?

See proposition




  • Explain that CSU is a benign skin condition with a non-allergic causal mechanism that can stop spontaneously after a few weeks, months or years.
  • Explain that diet is not an issue in CSU. However, you may suggest that the patient keep a diary of food intake and CSU flare-ups for a period of 15 to 30 days to reassure the patient that his diet is not responsible. It is not recommended to propose a systematic food avoidance diet.
  • Explain that non-steroidal anti-inflammatory drugs (including ibuprofen) may promote urticaria flare-ups through a pharmacological mechanism on leukotrienes (non-allergic reaction).


  • The treatment depends on the patient’s level of discomfort. It is necessary to assess the impact of CSU on his quality of life (using the DLQI or CU-QoL scores) and the severity of CSU (UCT and UAS7 scores).


  • Mizolastine should be discontinued due to the risk of QT prolongation with escitalopram.
  • Ranitidine should be discontinued because it is ineffective in this patient, and there is no evidence in the literature of the efficacy of anti-H2 antihistamines in CSU.
  • Prescribe an anti-H1 antihistamine that does not prolong the QT (e.g. cetirizine, levocetirizine) by suggesting 2 doses/day for 1 week, then 3 doses for 1 week, then 4 doses (2 in the morning, 2 in the evening) in case of ineffectiveness. *Most experts recommend proceeding directly to 4 doses of anti-H1 antihistamines and then decreasing to 3 and then to 2 after achieving remission.
  • Propose a follow-up at 1 or 2 months to discuss further treatment in case of failure and depending on the severity of CSU and its impact on the patient’s quality of life.

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