ECHOGRAPHIC EVALUATION WITH IMAGE-ANALYSIS OF HISTAMINE-INDUCED WHEALS

10 healthy, non-atopic women, aged 20-30, underwent histamine prick te sts, performed in duplicate on the volar surface of the forearm with p rogressively increasing histamine concentration, from elbow to wrist o n the left arm and from wrist to elbow on the right. Histamine wheal a ssessments were performed with the following methods at 5, 10, 15 and 20 min from challenge: planimetry for wheal area determination, A-scan ning for skin thickness evaluation and echographic image analysis for assessing skin edema corresponding to the hypoechogenic area in the de rmis. Wheal extension, skin thickness and edema of the dermis increase in time according to the histamine concentration. However, in respons e to the same concentration, regional variations consisting in greater wheal extension and dermis hypoechogenic areas were observed on proxi mal than on distal sites. Conversely, statistically significant differ ences were found between tests carried out on the right arm compared t o those on the left regarding skin thickness. These variations have to be considered when interpreting data derived from pharmacological stu dies on the inhibition of histamine-induced reactions.