We studied 66 patients allergic to mould Alternaria. 53% males and 47% females, with 60% diagnosed as having asthma versus 40% rhinitis, only 29% had allergy to Alternaria without any other cutaneous reactivity while 71% were polisensitized, more frequently to D. pteronyssinus, grass pollen, Cladosporium and cat epithelium. We compared the patients allergic to Alternaria with those allergic to grass pollen and D. pteronyssinus.