Discussion
Chronic urticaria is a common medical condition, well-described in the
adult population. Data regarding CSU in children is scarce. In the
current report, we aimed to better characterize this disorder in a large
cohort of children with a long follow-up period. We found that pediatric
CSU is frequently accompanied by atopic diseases and has a favorable
outcome.
The study cohort had an encouraging clinical course. CSU was not
accompanied by angioedema in most children and there was a good clinical
response to regular doses of antihistamines, without need for additional
medications. In most cases, hives persisted for no longer than two years
and relapses were rare. These findings are supported by previous smaller
series that found CSU in children is a disease with good prognosis.2,9,13 In accordance with the favorable outcome,
laboratory tests in our cohort were within the normal range. Probably,
indicating that routine laboratory tests in children with CSU are not
essential. This notion is supported by Grattan et al. who left the
decision to perform laboratory tests in cases of CSU to the discretion
of the treating physician.4
Traditionally, CSU is considered a disease of unknown etiology.
Nonetheless, in some patients, an underlining autoimmune mechanism may
be present. This concept is supported by the fact that, in adults,
autoimmune diseases, mostly affecting the thyroid gland, frequently
accompany CSU.6 Moreover, a canonic work by Hide et
al. 32 reported autoantibodies against IgE and its
receptor, as a potential trigger for the disease. These findings
established the notion that CSU is a TH1 derived phenomenon. Atopy,
including AD, AR, food allergy and asthma are considered TH2-related
diseases. In the current study, one-third of the children with CSU had
at least one atopic disease. AD and AR were significantly more prevalent
in children with CSU, as compared to the general pediatric population in
Israel and in the world. Food allergy was significantly more prevalent
in children ages 4 to 12 years, with CSU, as compared to the general
pediatric population. An exception is the difference in the prevalence
of asthma; although higher in children with CSU than in the general
pediatric population, it did not reach significance.
It can be speculated that the high prevalence of atopic comorbidities
can be attributed, in part, to confusion between CSU and AD. When
patients with AD were excluded from the analysis, the prevalence of
other atopic diseases and the significant differences between patients
with CSU and the general pediatric population remained similar.
High levels of IgE were found in more than half of the results. This
finding did not overlap with the patients with clinical atopy. This
laboratory abnormality might provide additional support to the underling
atopic background accompanying these children.
The co-existence of atopic diseases had no effect on the likelihood of
relapsing or on the duration of CSU. These findings are in concordance
with other studies that showed a similar prevalence of atopic diseases
in smaller cohorts of pediatric patients with
CSU.5,8,9 Recently, one large cohort, that included
Israeli adolescents, showed a robust link between CSU and atopic
diseases.7 These publications all support the
assumption that there is a subgroup of CSU patients with TH2-driven
disease.
This study is subject to the limitations inherent to any retrospective
work; some of the data were incomplete. As the follow-up period was very
long, changes in the treatment modalities for CSU were inevitable.
Treatment with anti-IgE was approved for children with CSU older than 12
years of age, only at the end of the follow-up period. As such, its
effect on childhood CSU was not evaluated in this study.
In conclusion, CSU in children is mostly a mild disease. It does not
tend to relapse and can be managed with antihistamines alone. Atopy was
found to be prevalent in children with CSU. However, these atopic
diseases did not influence the duration or severity of the disease.
Whether CSU in children should be part of the spectrum of atopic
diseases requires further investigation in larger, prospective studies.