Library

Notes: Four cases of infants with atopic dermatitis are reported. In all cases, a sensitization to peanut is demonstrated. Any ingestion of peanuts can be excluded, with the exception of a daily consumption of peanut oil, contained in milk formulas. Oral challenges with peanut oil induce a rash, and elimination of these brands is followed by the disappearance of eczematous lesions. The presence of residual allergenic proteins in peanut oil is thus suspected. Owing to the growing incidence of peanut hypersensitivity, the elimination of peanut oil from all milk formulas, food for babies, and ointments, seems to be highly advisable.

Notes: Histamine plays a key role in the pathogenesis of chronic urticaria (CU). The authors of this paper have studied the effects of ingested histamine in 25 patients with CU. A 120 ing dose of histamine. well-tolerated in the healthy subject, was instillated into the duodenum. Concomitantly. plasma histamine (H) levels and plasma and urinary methylhistamine (MH) levels were measured. Intraduodenal administration of histamine was responsible for the development of an attack of urticaria in 64% of patients, while control subjects were asymptomatic. Plasma histamine levels were significantly higher after digestive histamine challenge (DHC) in patients with CU compared with controls. An abnormal increase in plasma histamine was observed in 72% of them. Plasma MH exhibited the same kinetic behaviour with a usually delayed time-pattern. Urinary MH concentration was higher in patients presenting with early-onset urticaria during the first hour than in those with the late-onset type between 1 and 12 hr after DHC. The coefficient of mcthylation (plasma MH/MH + H) was not significantly different in patients presenting with an attack of urticaria following DHC and in other subjects, Urinary excretion of MH and urinary flow increased significantly in patients presenting with an attack of urticaria following DHC which corresponds to increased absorption of histamine during the 5-hr period following DHC and its role on excretion by the kidney via vasodilation which it induces. This study demonstrates the abnormal frequency of disturbances in the metabolism of exogenous histamine in patients with CU. Increased plasma H accounts for the abnormal passage of H across the intestinal barrier which can result either from intestinal hyperpermeability and/or a deficit in the enzymatic catabolism of histamine. The systems of methylation and urinary clearance of MH appear to be effective. It is thus postulated that there is a deficit in diamine oxidase (DAO) in the enterocyte. The lack of correlation between the kinetic behaviour of plasma H and the onset of urticaria draws attention to the extent of individual variability in skin reactivity to histamine.

Notes: Abstract. Seven hundred patients were investigated prospectively before undergoing chemonucleolysis. A past history of allergy and/or previous exposure to papain, either in food, beverages or drugs, was sought, and a skin-prick test with chymopapain was performed. Based on the results obtained, the subjects were classified into four groups: Group I– 225 non-atopic non-papain-exposed subjects; Group II–285 non-atopic papain-exposed subjects; Group III–69 atopic non-papain-exposed subjects; and Group IV– 121 atopic papain-exposed subjects. Latent sensitization to papain was observed in 0.4% of subjects in Group I, 3.16% in Group II, 5.8% in Group III and 7.4% in Group IV. The odds ratios were 13.8 for atopy and 7.3 for exposure to papain. Interaction between atopy and papain exposure did not result in a significantly greater risk. Neither sex nor age nor a history of a previous drug reaction were risk factors. Only one patient out of the 23 who were sensitive to papain had no risk factor. The 677 skin-test negative patients then underwent chemonucleolysis and none of them had an anaphylactic reaction. This was significantly less frequent: (P= 0-04) than the incidence in a random population (0.45%). Prick tests performed 6 weeks and 6 months after chemonucleolysis revealed newly acquired sensitization in 36% of the patients. Atopy was not a risk factor for this event. Three points are discussed: (i) the negative predictive value of skin-prick tests with chymopapain is confirmed; (ii) subjects likely to be sensitized are atopic and/or have been exposed previously to food or drugs containing papain and therefore they can be identified pre-operatively by a questionnaire; (iii) atopy is a risk factor for the induction of specific IgE to allergens internalized via a mucosal surface but not for those that are injected parenterally.