Diagnosis

According to the EAACI/GA2LEN/EDF/WAO urticaria guidelines, the underlying causes of CSU in children are similar to those in adults and so the same diagnostic approach should be taken (Zuberbier et al., 2018).

In the diagnosis of urticaria in paediatric patients, targeted laboratory testing should be only used where appropriate (Choi and Baek, 2015). The below table identifies what laboratory tests may be considered for different types of urticaria observed in paediatric patients (Table 1). Importantly, allergy tests must always be guided by patient history to avoid false positives. In addition, for patients with a suspected autoimmune cause for their urticaria, the B cell Histamine Release Assay is preferable to ASST due to the potential discomfort caused by the latter (Marrouche and Grattan, 2012).

Table 1: Relevant laboratory investigations for different types of urticaria in children. Adapted from Choi and Baek, 2015.

Relevant laboratory investigations for different types of urticaria in children. Adapted from Choi and Baek, 2015.


CSU severity is frequently assessed using the UAS7 score. A modified version of this scale has been used in paediatric patients to account for their smaller size and hence lower possible hive number. The modified UAS7 incorporates the following assessment over seven days (Potter et al., 2016):

Hives (wheals)

0 = symptom is absent

1 = mild:(1–<10 hives/24 hour)

2 = moderate: (10–30 hives/24 h)

3 = intense: (>30 hives/24 h or large confluent areas of hives)

Pruritus

0 = symptom is absent

1 = mild: present but not annoying or troublesome

2 = moderate: troublesome, but does not interfere with normal daily activity or sleep

3 = intense: severe pruritus, which is sufficiently troublesome to interfere with normal activity or sleep

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