[Chronic urticaria and toxocara canis infection. A case-control study].
BACKGROUND
The cause of chronic urticaria remains unknown very often. Having noted several cases of chronic urticaria associated with antibodies to Toxocara canis, and lacking any other explanation, we set-up a case-control study.


METHODS
Between November 1992 and April 1993, 51 adults or children with chronic urticaria (cases) who had been examined at least once at one of the three dermatology units of the Bordeaux University Hospital were matched to controls who had neither signs nor symptoms of chronic urticaria. The presence of antibodies to T. canis was measured by ELISA and Western blot.


RESULTS
The frequency of T. canis was 64.7 p. 100 in cases and 21 p. 100 in controls (p < 0.0001) with an odds ratio of 6.9 (95 p. 100 CI: 2.9-16.3). Cases with antibodies to T. canis were more frequently in contact with pets (84 vs 50 p. 100, p < 0.001). Of the 33 cases of chronic urticaria with antibodies to T. canis, 14 have been treated with thiabendazole or ivermectin and after a one-year follow-up, 5 (36 p. 100) were cured and 4 (29 p. 100) had improvement. No improvement occurred in the 12/19 cases not specifically treated.


CONCLUSIONS
The strong association between the presence of antibodies to Toxocara canis and chronic urticaria is unlikely to be due to chance. A causal relation is difficult to establish, however. Our findings should prompt further investigation of a role for Toxocara canis in chronic urticaria and the evaluation of therapeutic interventions. Preventive measures include deworming pets (dogs particularly), enclosing kitchen gardens, and handwashing before meals. A systematic measure of Toxocara canis in patients with chronic urticaria is recommended especially when in contact with dogs. Early and specific treatments can be applied on knowledge we already have.
Wolfrom
E
E
Unité de Dermatologie pédiatrique, CHU de Bordeaux.
Chêne
G
G
Lejoly-Boisseau
H
H
Beylot
C
C
Geniaux
M
M
Taïeb
A
A
D000328:Adult; D000818:Animals; D000909:Antibodies, Helminth / Q000032:analysis; D000969:Antinematodal Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D002908:Chronic Disease; D004285:Dogs; D005260:Female; D006801:Humans; D008297:Male; D013827:Thiabendazole / Q000627:therapeutic use; D017166:Toxocara canis; D014120:Toxocariasis / Q000150:complications* / Q000188:drug therapy / Q000276:immunology; D014581:Urticaria / Q000209:etiology* / Q000276:immunology
D000909:Antibodies, Helminth; D000969:Antinematodal Agents; D013827:Thiabendazole
Urticaire chronique et Toxocara canis. Etude cas-témoins.