 National study of current practice, multicentric, randomized, open All oral provocation tests will be randomized, double blind Study treatment. For oral provocation test, placebo with NeocatePasteurized half skimmed milk available in standard outlets from 0.1 to 0.8 mLday Tests At M0 :1 Clinical examination 2 Biological test blood sample 16.5 mL : WBC, ferritin, total IgE, specific IgE, cow milk, ALPHALACTALBUMIN , casein, BETALACTOGLOBULIN and goat milk using RASTSpecific secretory IgA by ESPCI frozen salivaBiologic collection- Specific immunoglobulins against cow milk, ALPHALACTALBUMIN, casein, BETALACTOGLOBULIN, quantification of IgM, sub classes of IgG and IgA by ESPCI frozen serum. 