Immediate and late phase allergic cutaneous reactions are not inducers of unspecific or specific local hyperreactivity

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Abstract
The present study evaluates the possibility of allergen-induced unspecific and specific dermal hyperreactivity with special reference to the presence of late cutaneous reactions and allergen-induced nasal hyperreactivity. Twenty-six patients with strictly seasonal allergic rhinitis participated. All had a positive skin prick test for birth (Betula verrucosa) and/or timothy (Phleum pratense). Ten patients had previously displayed an allergen-induced nasal hyperreactivity and six patients a late cutaneous reaction. An initial skin prick test with a relevant pollen allergen was done in triplicate. The immediate skin reactions were recorded after 15 min and any late-phase reaction after 6 h. Twenty-four hours later the patients were retested. The same pollen allergen was sited in the first flare reaction from the previous day. A histamine prick test was sited in the weal as well as in the third reaction from day 1. A histamine control was also performed in a previously unaffected area. The allergen-induced weal reactions decreased significantly at rechallange compared with the results from the previous day (P < 0.05). The histamine tests resulted in similar skin reactions regardless of whether or not they were done on a previous allergen test site. This was true for both specific and unspecific reactions when the subgroups of patients with previously demonstrated allergen-induced hyperreactivity or late-phase skin reactions were evaluated separately. These results indicate that allergen-induced hyperreactivity is not a general feature of allergic inflammation but is a phenomenon restricted to specific sites, such as the airway mucosa.