The goal of this clinical trial is to learn if platelet-rich plasma (PRP) works to treat acral stable vitiligo in adults. It will also learn about the safety of platelet-rich plasma. The main questions it aims to answer are:

• Does PRP combined with 308 nm excimer phototherapy improve the efficacy compared to 308 nm excimer light alone in the treatment of vitiligo of the extremities?
• What medical problems do participants have when taking PRP intradermal injections?

Researchers will compare PRP to a placebo (a look-alike substance that contains no drug) to see if PRP works to treat acral vitiligo.

Participants will:

• Receive PRP intradermal injections once a month and 308 nm excimer phototherapy twice a week, or the same frequency of saline injections and phototherapy for 6 consecutive months
• Visit the clinic once every 1 month for evaluations
• Keep a diary of their symptoms or side effects during follow-up

Vitiligo is an acquired skin disorder characterized by depigmented macules, and one of the conventional treatment principles is to promote the differentiation of stem cells at the follicular bulge into melanocytes, but vitiligo of the extremities is clinically difficult to repigmentation and resistant to treatment due to its lack of hair follicles. Platelet-rich plasma (PRP) is a concentrated platelet plasma obtained by in vitro isolation of autologous whole blood, and its effect on repigmentation of vitiligo at the extremities and the potential mechanism remain unclear. The investigators investigated the efficacy of PRP on acral vitiligo by a single-center, prospective, self-controlled clinical study.

Inclusion Criteria:

• Patients with non-segmental vitiligo stable for more than half a year;
• At least 1 separate stable lesion on each of the dorsum of the right and left hands, proximal fingers, distal fingers and palms;
• The area of white spots is less than 10 % of the total body surface area and more than 1 % of the total body surface area;
• Those who have not received systemic treatment of vitiligo and phototherapy or related treatments within 1 month ≥ 1 year without significant efficacy;
• Voluntary signing of informed consent.

Exclusion Criteria:

• Pregnant and lactating women;
• Those who have used glucocorticoids or other immunosuppressants in the last 3 months;
• Suffering from haematological disorders such as coagulation abnormalities and thrombocytopoietic disorders;
• Those who are allergic to ultraviolet light and photosensitive treatment;
• Scar constitution;
• Those with current or previous history of skin cancer or family history of skin cancer;
• Those with infectious diseases such as HIV, syphilis, hepatitis B or C;
• Those with other serious systemic diseases;
• Patients who, in the judgement of the investigator, are not suitable for inclusion in this trial.