1/2. Selective allergy to sheep's and goat's milk proteins.BACKGROUND: Cow's milk proteins are amongst the most common causes of food allergy in infants, and caseins are probably the main allergens. The existence of a high degree of cross-reactivity between milk caseins from different animals has been reported. We describe a 2-year-old boy who experienced allergic reactions after eating and touching sheep's cheese, but who tolerated cow's milk and cow's milk dairy products. He had never ingested milk or milk derivatives from sheep or goat. methods: Skin prick tests were carried out using whey fractions of cow's milk, whole milk and casein from goat, sheep and cow. We also performed skin prick tests with enzymes used in cheese production. Prick-by-prick tests with cheese made from cow, sheep and goat and their corresponding whole milk were also performed. Total serum IgE and specific IgE to cow's milk proteins, whole cow's milk and sheep's milk were determined. Specific IgE against casein and whole milk from the three different species were determined by ELISA. Inhibition of IgE binding to bovine casein was tested for casein and whole milk from all three species. The proteins of three types of casein and whole milk from cow, sheep and goat were separated by SDS-PAGE and were incubated with the patient's serum. RESULTS: skin tests were positive to sheep's milk and goat and sheep casein and were negative to all cow's milk proteins and whole cow's and goat's milk. Prick-by-prick tests were positive to goat's and sheep's cheese and were negative to cow's cheese. In ELISA-inhibition, sheep's milk and goat and sheep casein were able to inhibit > 50 % of specific IgE binding to sheep casein. The results of immunoblotting showed that the patient's circulating IgEs recognized only one band in the lanes corresponding to sheep and goat casein. CONCLUSIONS: We report a patient with allergy to sheep's and goat's milk proteins but not to cow's milk proteins. sheep casein was probably the main allergen causing sensitization in this patient. The results suggest that sheep casein shows a high degree of cross-reactivity with goat casein but not with cow casein. Our patient presented allergic symptoms caused by sheep and goat milk and cheese proteins. However, he was able to tolerate cow's milk and cow's milk dairy products without any ill effects.- - - - - - - - - - ranking = 1keywords = goat (Clic here for more details about this article) |
2/2. Allergic contact dermatitis from salicyl alcohol and salicylaldehyde in aspen bark (populus tremula).Salicyl alcohol or 2-methylolphenol is a well-known allergen in phenol-formaldehyde resins and a strong sensitizer in guinea pigs. There is 1 previous report of allergic contact dermatitis from salicyl alcohol in aspen bark. We describe a second case with concomitant allergy to salicylaldehyde. An elk researcher who had handled leaves from various trees presented with eczema of the hands, face, flexures, trunk and extremities. Patch testing showed sensitivity to salicyl alcohol, salicylaldehyde, balsam of peru (myroxylon pereirae resin), aspen wood dust and an extract prepared from the bark of aspen (populus tremula). Weaker reactions were observed to bark extracts of rowan (sorbus aucuparia), tea-leaved willow (salix phylicifolia) and goat willow (salix caprea). We analysed salicyl alcohol and salicylaldehyde in the bark extracts and found the 2 chemicals in equal amounts, about 0.9 microg/mg in aspen bark and in lower concentrations in rowan and the willows. We did not find either of the chemicals in the test substance of balsam of peru (myroxylon pereirae). Besides salicyl alcohol, salicylaldehyde is also recommended to be used to screen for contact allergy to aspen. Both of these chemicals should be tested in forest workers in areas where aspen is growing.- - - - - - - - - - ranking = 0.0625keywords = goat (Clic here for more details about this article) |