A new concept in allergology is that of “local” IgE production on respiratory and ocular membranes causing allergy and also called Local Allergic Rhinits. The allergic reaction in this case is very localised to the nasal membranes and conjunctiva and not identified on routine allergy skin prick testing or RAST blood testing. However these patients respond to allergy treatment although testing negative for allergies. Many will develop symptoms if exposed to an allergen (Provocation Testing). In the past they would have probably been told they had no allergies at all!
Local IgE production can be triggered by pollens and house dust mites and checking a nasal mucus sample will show allergy cells called Eosinophils.
Diagnostic approach in patients with LAR. J Allergy Clin Immune 2012 Jun;129(6): 1460-7