Seventy- four patients will be included in the study after taking informed consent/ assent. They shall be randomly divided into two groups of thirty- seven each using a random table method. One group (Group A) will apply topical 5% cysteamine cream over melasma patches for 15-30 minutes at bedtime initially which will be gradually increased to overnight application based on the tolerance of patient and the other group (Group B) will have overnight application of topical 4 % hydroquinone cream at bedtime for the duration of 9 weeks. Each patient will be followed up at 3 weekly intervals (3, 6 ,9). Another follow up visit will be conducted at 4 weeks after completing the course of treatment.

Common and important adverse effects such as redness, dryness, itching, burning, irritation, and dyspigmentation shall be explained to the patients. To assess for adverse effects, patients will be provided with a check list of possible side effects at every visit. Adverse effects reported by participants will be categorized according to the Numerical Rating Scale (NRS) in which each adverse effect will be assigned a numerical score ranging from 0 to 10, with 0 representing no side effect and 10 representing an extremely severe side effect. Patients will be asked to choose the number that corresponds to the severity of their symptom. In case a patient experiences severe redness, irritation, or hyperpigmentation (Numerical Rating Scale 7 or more), they will be removed from the study and treated with the appropriate therapy for those adverse effects and started on alternative treatment for melasma. During treatment, they will be advised strict photoprotection by avoidance of sun exposure and physical protection as well as use of physical sunscreen whenever outdoors. They will be strictly cautioned against the use of any unprescribed topical agent, fairness cream, or any facial cosmetic procedure which may interfere with the therapeutic outcome.

Assessment of improvement for efficacy of therapy will be done by dermoscopic evaluation and by calculating the mMASI score of the face at each visit (3, 6 and 9 weeks) and 4 weeks later after completion of treatment.

Primary outcome measures

1.     Reduction in melasma severity assessed using the modified Melasma Area and Severity Index (mMASI) score.

2.     Reduction in pigmentary lesions assessed through clinical photography and dermoscopic evaluation.

Secondary outcome measures

1.     Patient-reported outcomes: Evaluation of treatment satisfaction and improvement in melasma.

2.     Adverse effects: Monitoring and categorization of adverse events related to each treatment using the Numerical Rating Scale (NRS).

At the end of this study, means of mMasi score from both groups will be calculated separately and the mean of difference between both groups will be compared. The response of patients towards improvement will be graded as per their level of self-satisfaction at the end of study as:

§  Poor response rate= 0-25% reduction

§  Fair response rate= 25-50% reduction

§  Good response rate=50-75% reduction

§  Excellent response rate=75-100% reduction

Clinical as well as dermoscopic photographs will be taken and labelled by specific numbers for each patient before starting the treatment and at each follow up visit and 4 weeks later after completion of treatment.