In this study, the investigators demonstrated that in vivo THG microscopy can differentiate vitiligo lesions and normal skin based the optical nature of melanin. This THG-based procedure provides a valuable tool for noninvasive determination of third-order nonlinear susceptibility of melanin within the skin. It can also provide real-time histopathology information for treatment follow-up, without performing invasive skin biopsy.

The investigators initiate this open, randomized, left-right comparative study to evaluate the efficacy of pulsed ultrasound in the treatment of vitiligo on the face or trunk. Face is included in this study because vitiliginous lesions on the face has a better treatment response and causes more psychological distress on the patients than vitiligo affecting other body areas. Thirty adult subjects with vitiligo affecting the face or trunk symmetrically will be recruited. After randomization, subjects will be administrated their ulrasound treatment twice a week for 24 weeks. Their original topical treatment and/or phototherapy will be continued. During follow-up visits, digital photographs will be taken for evaluating the extent of residual depigmentation. In vivo harmonic microscopy and three skin biopsy specimens will be performed at the indicated time points on the depigmented, repigmented areas and surrounding normal skin.

Inclusion Criteria:

1. 20-75 years old
2. With skin type Ⅲ or Ⅳ
3. With Vitiligo
4. Can read the informed consent form
5. Can continue the original treatments

Exclusion Criteria:

1. With segmental vitiligo.
2. Have joined other clinical trials