Cross reactions in skin tests between house dust mite extract and feather extract

Of 248 patients skin tested with house dust mite extract and feather extract 102 gave reactions with both, thirty-one with mite extract alone and four with feather extract alone. It is believed that nearly all the reactions to feathers were due to mite allergens in the feather extract. As the extract was not made from feathers from old upholstery it is suggested that the reactions might be due to a poultry mite having cross-antigenicity with the house dust mite.