Skin prick test digital imaging system with manual, semiautomatic, and automatic wheal edge detection and area measurement

A novel biomedical instrument for supporting the physician in Skin Prick Testanalysis was designed, developed, characterized, and is now ready for clinical trials. SkinPrick Test is the gold standard front-end analysis for diagnosis of allergies in human subjects.The forearm skin is punctured with different allergens and the resulting reaction wheals areanalyzed and compared to standard reaction, with larger areas corresponding to strongerallergy to the specific allergen. The wheals inspection and allergy diagnosis are performed,visually and subjectively, by the Medical Doctor. This procedure is laborious and somehowunreliable, being subject to variability both intra- and inter-operator because the doctorsubjectivity in detecting and measuring the wheals is significant. Registration of the examresult is rarely available in a digital format, useful for data saving, transmission, retrieval andcomparative analyses. Many of the above criticalities of the actual Prick Test manual practiceare addressed and resolved by the proposed biomedical instrumentation that makes use ofdigital image-processing and data storage. In this work, we present a prototype of whealmeasurement system, designed, developed and characterized to specifically measure geometry and areas of the allergic reaction wheals in Prick Test clinical exams. After softwaredevelopments from previous version of the instrument, the wheal-meter now allows manual,semi-automatic, automatic, and fully-automatic operating conditions always providing digitalexams output.