The goal of this clinical trial is to learn about accuracy of teledermatology in patch test interpretation in patch test's patients population. The main question[s] it aims to answer are:

• Accuracy of teledermatology in patch test interpretation by dermatologist
• Accuracy of teledermatology in patch test interpretation by Residency
• Accuracy of teledermatology in patch test interpretation by Scitentist
• The factors influencing the interpretation of remote dermatologic patch test results from photographs of patients.

Participants will

• do patch test in Siriraj hospital and come to follow up at 48 hr and 72 hr for interpretation of patch test
• take a photo at home and sent the photo to contact clinic via online application or email on the day of 48 hr, 72 hr and 7 days following the interpretation of patch test

Researchers will compare in-clinic group and telephoto group to see if the accuracy of patch test interpretation is more or less.

Inclusion Criteria:

• Participants in the study must be 18 years of age or older.
• Participants in the study must have undergone patch testing for contact allergies.
• Participants in the study should be able to take photos of test results on their back and/or arms using a mobile phone or personal camera, and send them to the researcher through the Line application and/or email within 48 hours, 96 hours, and on the 7th day.
• Participants in the study should be able to read and comprehend the questionnaire in Thai and respond to the questionnaire independently.
• Participants in the study must have at least one positive result in the patch testing.
• Participants in the study must provide consent to participate in the study by signing the informed consent document.

Exclusion Criteria:

• Participants in the study who are unable to attend follow-up appointments for result assessments.

Prohibited from laws (and/or rules,regulations,contracts), Fear of inappropriate use of data