Facial thermography during nasal provocation tests with histamine and allergen

Changes of skin temperature (T degree) of the nose area during nasal provocation tests with histamine and allergen were followed by means of an infrared thermography camera. By a colimator system in which temperatures measured on a given surface can be integrated and averaged, thermography allows the continuous and quantitative recording of the temperature during the whole procedure in a completely noninvasive way. In 10 normal subjects, increasing doses of histamine induced a dose-dependent rise of the nose external temperature. No significant change was observed with the vehicle solution. In six subjects allergic to grass pollen, the nebulization of increasing concentrations of a pollen extract induced a dose-dependent rise in T degree. The T degree rise observed after histamine or allergen corresponded to a marked nasal obstruction. The nebulization of the highest dose of the pollen extract did not induce any T degree rise in six nonallergic subjects. The continuous recording of the skin temperature by a noninvasive method might yield additional information on the vascular changes rapidly occurring during nasal challenges.