The aims of this study are to:- Compare the effect of fractional Erbium: YAG laser assisted delivery of platelet- rich plasma versus microneedling with platelet-rich plasma in the induction of skin repigmentation in localized stable vitiligo patients.

Vitiligo is a depigmentation disease characterised by epidermal melanocyte death and melanin loss. It affects less than 0.1% to greater than 8% of the world's population. It is caused by a dynamic interplay between genetic and environmental risks that initiates an autoimmune attack on melanocytes in the skin. There are some treatment modalities, such as topical steroids, topical calcineurin inhibitors, excimer laser, narrowband-ultraviolet B therapy (NB-UVB), vitamin D,and non-cultured epidermal cell suspension (NCES).

One of the representative autogenous regenerative biomaterials is platelet-rich plasma (PRP) which contains moderate to high concentrations of platelets together with multiple biomolecules and moderate concentrations of leucocytes. Activated platelets can release autogenous growth factors that may initiate a signalling cascades and lead to numerous intracellular changes, promoting the proliferation, migration, and differentiation of stem cells and regulating local inflammation and immune responses.

Laser- assisted drug delivery (LADD) functions by creating focused zones of selective epidermal damage thereby rendering the dermis more accessible to topical medication.

Multiple lasers have been applied for the purpose of LADD, including ablative fractional carbon dioxide (CO2) and erbium-doped yttrium-aluminum-garnet (Er: YAG) lasers.

Microneedling (Mn) is a minimally invasive process in which many tiny needles penetrate the skin. It augments transdermal drug delivery (TDD) through the creation of pores in the stratum corneum. This technique is also believed to induce pigmentation by physically moving melanocytes with the needles into the vitiligo areas from the pigmented areas, so that they may serve as reservoirs for melanogenesis, also it induces microinflammation which stimulates the migration of keratinocytes and melanocytes that induces the release of cytokines and growth factors stimulating melanocytes at the periphery of vitiligo patches and their migration from pigmented to unpigmented areas.

Inclusion Criteria:

- 1) Patients of both sexes with stable localized vitiligo: stable patches (should not have any increase or decrease in size or pigmentation for at least 3 months) .

2)Age between 10 - 60 years

Exclusion Criteria:

• 1)Acute or chronic infections. 2) Koebner phenomenon. 3) Contraindications to PRP injections:

  • Patients with blood or platelet abnormalities.

  • Patients taking anti-platelet drugs or anticoagulants.

  • Patients with a history of altered or abnormal fibroblast function, such as collagen diseases or myelofibrosis.

    4) We also excluded pregnant or lactating women. 5) All patients included had not received any local or systemic medication for at least 2 months before the study.