Progress in understanding hypersensitivity drug reactions: an overview

The common triggers of urticaria in children admitted to the pediatric emergency room

BACKGROUND

Urticaria frequently causes pediatric emergency department (PED) admissions. Children with urticaria may unnecessarily avoid suspected allergens. We aimed to investigate the possible and exact triggers of urticaria in children admitted to the PED.

METHODS

Medical records of children admitted to the PED within a 1-year period were evaluated for the International Classification of Diseases 10 (ICD-10) L50 urticaria code, noting symptoms, and possible triggers of urticaria. We performed telephone interviews to complete the missing data and further diagnostic tests for IgE-mediated allergies to identify the exact triggers of urticaria.

RESULTS

Among 60,142 children, 462 (0.8%) with the L50 code were evaluated. Possible triggers based on the history and physical examination could be identified in 46%: infections (18%), drugs (11%), foods (8%), infections and drugs (3%), insects (3%), pollen (1%), blood products (0.4%), and vaccines (0.4%). The most frequent infections related to urticaria were upper respiratory tract infections (74.5%), urinary tract infections (13.2%), gastroenteritis (8.2%), and otitis media (4.1%). After a diagnostic workup, IgE-mediated allergic diseases were diagnosed in 6% of patients. Twenty-two percent of the patients had multiple PED admission for the same urticaria flare. Urticaria severity was found to be the most important risk factor for readmissions to the PED (odds ratio: 3.86; 95% confidence interval: 2.39-6.23; p < .001). No relationship between urticaria severity, duration, and the triggers was present.

CONCLUSIONS

Despite detailed diagnostic tests, IgE-mediated allergic triggers were rarely the cause of urticaria in children admitted to the PED. Infections are the most frequent trigger. Severe urticaria causes more frequent readmissions to the PED.

High-dose anti-histamine use and risk factors in children with urticaria

AIM

The drugs of choice in the treatment of urticaria in children are H1-antihistamines. The aim of the study was to evaluate children with urticaria and define risk factors for requirement of high-dose H1-antihistamines in children with urticaria.

MATERIAL AND METHODS

The medical data of children who were diagnosed as having urticaria admitted to our outpatient clinic between January 2014 and January 2016 were searched. The medical histories, concomitant atopic diseases, parental atopy histories, medications, treatment responses, blood eosinophil and basophil counts, and serum total IgE levels were recorded. In addition, the urticaria activity score for seven days, autoimmune antibody tests, and skin prick test results were evaluated in children with chronic urticaria.

RESULTS

The numbers of the children with acute and chronic urticaria were 138 and 92, respectively. The age of the children with chronic urticaria was higher than that of those with acute urticaria (p<0.0001). There was no difference between the two groups in terms of blood eosinophil and basophil counts, and serum total IgE levels (p>0.05). There was a negative correlation between blood eosinophil count and the UAS7 score in children with chronic urticaria (r=-0.276, p=0.011). Chronic urticaria and requirement of high dose H1-antihistamines were significant in children aged ≥10 years (p<0.001, p=0.015). High UAS7 score (OR: 1.09; CI 95%: [1.03-1.15]) and basopenia (OR: 6.77; CI 95%: [2.01-22.75]) were associated with the requirement of high-dose H1-AH in children with chronic urticaria.

CONCLUSION

The requirement of high-dose H1-antihistamines was higher with children's increasing age. Disease severity and basopenia were risk factors for the requirement of high-dose H1-antihistamines.

Mediator release after nasal aspirin provocation supports different phenotypes in subjects with hypersensitivity reactions to NSAIDs

BACKGROUND

Multiple NSAID-induced urticaria/angioedema (MNSAID-UA) is an entity well differentiated from aspirin-exacerbated respiratory disease (AERD), although no detailed phenotype analysis has yet been performed. The objective was to evaluate the functional characteristics of MNSAID-UA subjects by analyzing the response to nasal lysine-aspirin challenge and measurement of nasal inflammatory mediator release compared with AERD subjects and controls.

METHODS

The study included 85 subjects with confirmed hypersensitivity to NSAIDs (≥3 episodes with >2 different NSAIDs or positive drug provocation) with either cutaneous (MNSAID-UA, n = 25) or respiratory manifestations (AERD, n = 60) and 30 tolerant controls (15 aspirin-tolerant asthmatic patients and 15 healthy controls). Nasal lavages at 0, 15, 60, and 120 min after lysine-aspirin challenge were analyzed for ECP, tryptase, PGE2 , PGD2 , LTD4 , and LTE4 .

RESULTS

Lysine nasal challenge was positive in 80% of the AERD cases but positive only in 12% of the MNSAID-UA group. MNSAID-UA subjects showed no changes in nasal ECP, whereas subjects with AERD had increased levels of ECP, with the highest peak at 15 min after challenge (P < 0.05). Tryptase levels were higher in AERD compared with MNSAID-UA and controls with the highest release of tryptase at 60 min (P < 0.05). Significant increases in PGD2 , LTD4 , and LTE4 were observed in AERD (at 60 min for PGD2 , LTD4 , and LTE4 ) but not in MNSAID-UA or control subjects (P < 0.05).

CONCLUSIONS

Data support the observation that MNSAID-UA, although sharing a common response with AERD to COX inhibitors, seems to have a distinctive phenotype, based on the response to nasal challenge and the release of inflammatory mediators.