One of the causes could be that he has acquired parasites. Ascaris, which are roundworms, can cause asthma and allergic symptoms; the eggs are commonly found and can live for years in soil and in house dust and rugs. Dogs often carry the worms. There are both medical and herbal treatments. The medical drugs treat for groups of similar parasites (roundworms, flatworms, flukes). The herbal herbal mixtures kill off a greater variety of parasites in case, as is likely, the child has acquired a variety of parasites.