Combination therapies best approach for melasma

The vast majority of agents used to treat melasma, including FDA-approved Tri-Luma (Galderma Laboratories), are hydroquinone-based, according to dermatologist William Baugh, M.D., assistant clinical professor at University of California, Irvine, School of Medicine and assistant clinical professor at Western School of Medicine, Pomona, Calif.

The good news is that a variety of other medications are clinically proven to help with melasma and are not hydroquinone-based. Some that have shown efficacy for melasma are tretinoin or the retinoids, azelaic acid, kojic acid, and adapalene, which is also categorized as a retinoid.

Knowledge base

There are several ways to categorize melasma.

"Even these classifications need refinement. We have known about melasma for centuries, but our understanding of it in well-controlled studies is still significantly lacking," Dr. Baugh tells Dermatology Times.

Don't assume melasma

Not all hyperpigmentation on the traditional areas where melasma occurs is actually melasma.

The three main documented etiologic factors for melasma are significant UVA/UVB exposure, use of oral contraceptives or hormone replacement therapy, and an underlying genetic predisposition.

A spectrum of drugs, including minocycline, can cause patchy hyperpigmentation. Likewise, topical exposure to certain plant-derived chemicals combined with sunlight exposure may produce an acquired patchy hyperpigmentation of the skin that may also mimic melasma.

"The most accurate way to make the diagnosis of melasma is to use an ultraviolet lamp - a Wood's lamp. This device also helps to classify the type and depth of the pigmentation into superficial, deep and compound types of melasma. Yet, the current classifications do not often take this into consideration," Dr. Baugh says.

Using the Wood's lamp, dermatologists will find that melasma that highlights is probably more superficial, while pigmentation that does not highlight as much is most likely deeper - either a compound or dermal type. Prognosis is based upon depth of pigment.

Misdiagnoses of lentigo maligna melanoma for melasma have occurred. This mistake could have fatal consequences.

"Keep the differential diagnosis in mind," Dr. Baugh says.

"If we look at the three main factors, then we can start to formulate our treatment plans to offset some of those. You cannot change genetics, and it is difficult, sometimes, to change someone's need for hormones. But with ultraviolet light exposure, we can make an impact," he says.

"For decades we have been able to block UVB, but blocking UVA is finally getting better," Dr. Baugh says.