1. To detect the efficacy and safety of combined TCA and MDA in treating melasma.
2. To compare the efficacy and safety of using different TCA concentrations (15% & 20%) alone and in combination with MDA in treatment of melasma.

Melasma is a common, acquired hypermelanosis that occurs in sun exposed areas, mostly on the face, occasionally on the neck, and rarely on the forearms.

Melasma is generally a clinical diagnosis consisting of symmetric reticulated hypermelanosis in three predominant facial patterns: Centro facial, malar, and mandibular The major clinical pattern in 50-80% of cases is the Centro facial pattern, which affects the forehead, nose, and upper lip .

The malar pattern is restricted to the malar cheeks on the face, while mandibular melasma is present on the jawline and chin .

A newer pattern termed extra-facial melasma can occur on non-facial body parts, including the neck, sternum, forearms, and upper extremities .

Using the Wood's light examination, melasma can be classified into four major histological types depending upon the depth of pigment deposition:The epidermal type, in which the pigmentation is intensified under Wood's light, is the most common type. The epidermal type is the most responsive to treatment.

Key etiologic factors include a genetic predisposition, solar damage, barrier abnormalities, and unique sensitivities to hormonal changes including pregnancy, oral contraceptives, and hormone replacement therapy.

Melasma is often difficult to treat, and the condition may be refractory. Despite a strong therapeutic demand, the treatment of melasma remains highly challenging with inconsistent results and almost constant relapses. The treatment of melasma should include a multimodality approach that incorporates photoprotective agents, antioxidant treatments, skin lighteners, exfoliants, and resurfacing procedures, as needed. Evidence-based studies suggest that first line therapies for melasma encompass intense photoprotection and topical lightening agents.

Many depigmenting agents and other therapies such as chemical peeling are used for treating melasma, in the form of mono or combined therapy .

The most commonly used peeling agents are alpha-hydroxy-acids, glycolic acid, Jessner solution, salicylic acid, trichloroacetic acid (TCA), pyruvic acid and phenol .

Chemical peelings are used on a wide scale in cosmetic field including melasma treatment. They often provide clinicians with flexibility in tailoring treat- ments according to patient needs and satisfaction Chemical peelings are used on a wide scale in cosmetic field including melasma treatment. They often provide clinicians with flexibility in tailoring treat- ments according to patient needs and satisfaction Chemical peelings are used on a wide scale in cosmetic field including melasma treatment. They often provide clinicians with flexibility in tailoring treat- ments according to patient needs and satisfaction. Chemical peelings are used on a wide scale in cosmetic field including melasma treatment. They often provide clinicians with flexibility in tailoring treat- ments according to patient needs and satisfaction.

Chemical peeling is a promising treatment for numerous pigmentary disorders as melasma. It aims to remove the melanin rather than the inhibition of melanocytes or melanogenesis by causing controlled necrosis and subsequent regeneration of the epidermis, apart from remodeling of collagen and elastic fibers in the dermis .

TCA is widely used peeling agent in treatment of hyperpigmentation especially melasma. It is a keratolytic acid which cause precipitation of proteins and coagulation necrosis of the epidermis that leads to reepithelization with replacement of smoother skin with an even skin tone .It is not expensive, stable, not light-sensitive and does not need to be neutralized .

Microdermabrasion (MDA) is a minimally invasive epidermal resurfacing procedure used to treat uneven skin tone/texture, photo aging, striae, melasma, and scars.Microdermabrasion uses a variable flow of vacuum suction to maintain contact with the skin whilst the crystals (or diamond tips) get to work by smoothing and buffing the skin's surface.The crystals (or diamond tips) cause gentle mechanical abrasion to the skin, which ultimately removes the stratum corneum layer of the epidermis. As part of the wound healing process, new epidermis forms with enhanced cosmoses. The technique is considered safe for all Fitzpatrick skin types and complications are minimal. In addition to the cosmetic benefits of MDA, studies have also shown improved skin permeability and enhanced delivery of transdermal medications dosed on an area of the skin treated with MDA. Microdermabrasion removes the stratum corneum, the outermost layer of the epidermis . MDA has also been shown to affect deeper layers of the epidermis and dermis. MDA causes a re-arrangement of melanosomes in the basal layer of the epidermis, flattening of rete ridges at the dermal-epidermal junction, increased collagen fiber density at the dermal-epidermal junction, and vascular ectasia in the reticular dermis .

Inclusion Criteria:

1. Adults of 18 years and above with bilateral melasma
2. Clinical diagnosis of melasma.
3. Mental capacity to give informed consent.

Exclusion Criteria:

1. Pregnant or nursing women
2. Current use of hormonal birth control medication or any hormonal therapy
3. History of laser or dermabrasion to the face within 9 months of study enrollment
4. Patients with poor wound healing, recurrent herpes simplex and current skin infection (facial warts, molluscum contagiosum) and history of hypertropic scar/keloids
5. Photosensitivity.
6. Patients with unrealistic expectations All the included patients will be subjected to detailed history taking,dermatological examination and Wood's light examination to estimate the depth (epidermal, dermal or mixed) of melasma.