Skin prick tests and RAST are practically equivalent, the first one having the advantages of low cost and immediate results. Both RAST and skin-tests are highly sensitive and specific. A negative result is very reliable in ruling out the presence of specific IgE against the tested allergen. However, in over 50 percent of cases a positive test is not associated by clinically relevant hypersensitivify. Many current indications, such as recurrent or persistent respiratory symptoms, vernal conjunctivitis, otitis, are incorrect and do not have any relationship with allergy. Detection of house dust mite and grass pollen sensitisation can identify in 95% of cases a child affected by respiratory allergy: if both tests are negative the probability of having another respiratory allergy is remote. Similarly, two allergens (egg and milk) are sufficient to identify as "atopic" a subject with dermatitis and to know that he will probably develop asthma, therefore to making decisions about therapeutic and preventive measures. In food allergy the use of prick-by-prick technique with fresh food is superior to RAST. Strong indications to perform RAST are limited to sting anaphylaxis and food related exercise induced anaphylaxis.
|Translated title of the contribution||Prick and RAST: Too many or too little|
|Number of pages||8|
|Journal||Medico e Bambino|
|Publication status||Published - Nov 30 2004|
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health