Proposition

Information

• Explain that CSU is a benign, non-contagious skin condition, not an allergic reaction. It may stop spontaneously after a few weeks, months or years.

Assessment

• Treatment depends on the impact of CSU on the child’s quality of life (assessable by the DLQI score; note that CSU severity scores are not validated for children). It is necessary to ask Louise and her parents about the discomfort CSU induces.

Treatment

• The 2 most-studied anti-H1 drugs in children are desloratadine and rupatadine (the latter is no longer available in oral solution since 2018). The dose may be doubled, tripled or even quadrupled if CSU is not brought under control, in increments of 1 to 2 weeks, if clinical tolerance is good (drowsiness in particular). ^*Some experts recommend proceeding directly to 4 doses of anti-H1 antihistamines and then decreasing to 3 doses and then to 2, after achieving remission.
• In case of CSU resistant to a quadruple dose of anti-H1 antihistamines:
  • if the impact on quality of life is low, propose that the 4 doses of anti-H1 antihistamines be maintained;
  • if the impact on quality of life is considerable and after at least 2 months of anti-H1 antihistamine failure, the data in the literature are scarce and do not allow recommendations to be made. Cyclosporine is the most-studied molecule in children under 12 years of age with CSU. ^*Experts are divided as to what course of action to adopt. Some propose the addition of montelukast (1 tablet/day), which is often proposed in childhood asthma, especially since there is a familial history of atopy; however, montelukast does not have a sufficient level of evidence to justify its use in CSU in children under 12 years of age, and its neuro-psychiatric side effects are more common in children than in adults. Some experts propose the addition of omalizumab, which is authorised for use in children from 12 years of age for CSU, but which has not been the subject of prospective studies in children under 12 years of age with CSU; this molecule has an MA for asthma in children from 6 years of age. Some experts propose the addition of cyclosporine, which does not have an MA for CSU in either children or adults, but has been the subject of the highest number of reported cases in children under 12 years of age and is taken orally; cyclosporine should be initiated at a dose of 3 to 4 mg/kg/day, after verification of renal function and exclusion of a chronic progressive infection. It requires clinical (weekly blood pressure tests) and biological monitoring (initially weekly, then monthly).
  • In conclusion, given the lack of consensus and the scarcity of data, it is preferable to seek advice from an expert centre.

References

• Treatment in case of failure with quadruple dose anti-H1 antihistamines in children under 12 yo.
• Montelukast treatment
• Scores (appendix 7)
• Appendix 8