Allergic diseases, which we call allergic reactions. For example, not every patient with asthma is atopic or has asthma even though he/she does not have an allergy. Therefore, those with atopic allergies are divided into atopic asthma, and those with atopy and not allergic to anything are divided into non-atopic asthma. Generally, approximately 40-50 percent of patients are predisposed. In atopic dermatitis, atopy is detected in approximately 30 percent of patients. In allergic diseases, atopy is positive in approximately 30 to 50 percent.
So just because you're not allergic to something doesn't mean you won't have an allergic disease. Allergic disease can occur without atopy or allergy.