Can the Mirena IUD cause melasma?

Anything that changes hormone levels can increase the risk of Melasma. Melasma needs a combination approach to get the best improvement and will need a series of treatments. First and foremost, always wear sunscreen daily. Cosmelan is a “gold standard” leave-on peel that has a high concentration of antioxidants and skin brightening actives that can used safely on all skin types especially skin types that have irregular pigmentation such as African American, hispanic, asian and mixed ethnicities. Its effects are to improve discoloration, hyperpigmentation, melasma, while also helping skin texture, pores, and acne scarring. Cosmelan inhibits tyrosinase, an enzyme in the melanin formation process, the process of your skin tanning. So the end result is a more even skin tone without as many irregularities. Other treatments in our practice, we combine Clear + Brilliant, peels, Microneedling/PRP, Aerolase, and sometimes Erbium Laser (coollaser) to get the best results. See an expert. Best, Dr. Emer

Unlikely to CAUSE melasma, however hormonal changes may contribute to melasma. More history is needed for an accurate answer. Having the Mirena taken out will not reverse melasma. 
Melasma is a very common cause of skin pigmentation. It can not be completely cured, however effective treatment are possible. This is because your skin is extremely sensitive to UV and even the smallest amount can stimulate your pigment cells to produce colour. The mainstay of treatment is strict UV protection- hats, sunglasses and SPF every 4 hours. This forms the foundation of all treatments. 

I prefer to use a combination of creams and laser for melasma. Hydroquinone can be used (5-8%), along with vitamin A creams or Meladerm. I start my patients on laser (low dose Q switch or Picosure) as this has shown to decrease pigment production by decreasing the activity of the cells that produce pigment. Laser itself is not aimed at ‘blasting’ pigment, but to slow down the rate of melanin production. Another laser I use is the Clear and Brilliant in the 1927 Permea setting combined with creams. IPL should never be used to treat mixed melasma as it often worsens the condition (this is termed ‘Rebound Melasma’) 

In some cases I combine glycolic AHA peels, and in other cases I use a tablet called Tranexamic acid to help. Melasma treatments should be tailored to each patient according the type of melasma. Majority of patients will have mixed dermal and epidermal melasma. Approach melasma as a medical condition and not a cosmetic concern, and the success rate will be much higher. 

Consult a Board Certified Laser dermatologist with a special interest in disorders in pigmentation as well as one who has experience in treating all skin types, including darker Ethnic skin. 

All the best, Dr Davin Lim. Laser, surgical and aesthetic dermatologist. Brisbane, Australia.