Evaluation of NIR
Patch testing was performed on the patient’s back, as described elsewhere22. Drugs were mixed in petrolatum 50% w/w at a final concentration of 20 mg. Readings were done at 48h and 72h after patch application, and if negative, patients were recommended to monitor the patch site to detect any eventual reaction. Due to the very low sensitivity of the test and the lack of systemic effects in cases with mild reactions5-10, in most instances all BLs were tested on the same day. In case of negative results, we proceeded to DPT as described5. DPT was considered positive if any objective symptoms indicative of an allergic reaction appeared during the treatment or within 48h after the last dose5.