HCM is your right choice.
Causes of melasma is as follows..
2. Oral contraceptive
3. Hormonal abnormality e.g.-LH, FSH, Thyriod Hormone, Estradiol
4. Ultraviolet ray / sunlight is a stimulating/ aggravating factor.
is not listed above, so it is not a cause of melasma.
Dr. M M Mahmud (email@example.com)