ALLERGIC MANIFESTATIONS FOLLOWING EATING SNAILS IN 12 PATIENTS WITH ACARIS ALLERGY - A NEW CROSSOVER ALLERGY

Twelve patients, with known respiratory acaris allergy, developed clinical manifestations following eating snails. In 7 cases this involved a typical asthma attack (5 times) or asthmatiform dyspnea (3 times), in 2 cases severe anaphylaxis and in 5 cases an erythematous and indurated reaction of the skin and subcutaneous tissue of the region of the arm in which acaris desensitisation injections had been administered during previous years. This skin reaction existed alone in 2 cases and in 3 was associated with other clinical manifestations. This sensitisation to snails was confirmed 9 times out of 12 by frankly positive prick-tests using commercial snail allergen. An oral challenge test was followed by the recurrence of clinical manifestations. This association between acaris allergy and snail allergy does seem to be linked to crossover allergenicity of certain components of these species. Preliminary results of immunobiological studies seem to indicate that, as has been previously suggested for marine molluscs, the problem is that of crossover reactivity with snail allergens, unmasked principally during cooking, rather than crossover allergy between house dust acaris and acaris of the species Riccardoella, a snail lung parasite. The severity of anaphylactic manifestations shown by several patients requires the more accurate determination of the incidence of snail allergy in patients with acaris allergy, in particular after specific desensitisation.