Severe itching conditions such as eczema or atopic dermatitis can have a significant impact on one's quality of life. Unfortunately, many of these conditions cannot be cured, and the focus is often on properly controlling or managing the condition. Thus, it is important to understand or objectively monitor how one's scratching behavior changes, based on medication or treatment or environmental conditions. In this work, we explore how wearable devices can support people with itching conditions to better manage their conditions. We carried out a three-phase study with 40 participants and 2 dermatologists to understand the implications of various system features and designs. Based on interviews with patients and doctors, we incorporated medical guidelines for treatment and patients' needs in the proposed Itchtector - a smartwatch-based mobile system to monitor itching behaviors and provide objective information about the user's scratching behaviors. Using the Itchtector prototype, we evaluated performance and possible acceptance with subjects.