Melasma: It’s complicated. It’s a unique form of photodamage that can have a vascular component, and new non-hydroquinone options are helping to address treatment gaps. But we do not yet have an optimal, effective and long-term treatment, according to dermatologist Pearl E. Grimes, M.D.
“Melasma is far more complex than we ever realized. As we get more data and look at pathogenesis pathways, we realize the true complexity of the condition. We know there’s a complex interplay of genetics, sun exposure, hormonal influences — even medications can trigger melasma,” says Dr. Grimes, who directs the Vitiligo and Pigmentation Institute of Southern California and is a clinical professor of Dermatology at UCLA. She presented on melasma at the 2019 American Academy of Dermatology annual meeting.
Melasma’s Link to Photodamage
Studies in recent years have revealed that melasma represents a unique phenotype of photodamage, which could signal a big shift in how dermatologists treat melasma, according to Dr. Grimes.
Melasma studies show, for example, that biopsies of the involved skin show an increase in solar elastosis, compared to uninvolved skin. Researchers have found that melasma biopsies exhibit damage to the basement membrane, which affects collagen. Biopsies of involved skin also show an increase in mast cells compared to those of normal skin. And there is a cohort of patients who have vascular melasma, where dermatologists see an increase in blood vessels and increased vascular endothelial growth factor (VEGF) in the affected versus nonaffected skin.
“All of this suggests it’s a form of photodamage,” Dr. Grimes says.
Moreover, involved skin areas show senescent fibroblasts.
“We also know that if you look at the pathways of what is upregulated in melasma lesions, there’s crosstalk between what is occurring in the epidermis and what’s happening in the dermis, as well,” she says. “The dermis and the epidermis are both impacting melanocytes and melanogenesis. Sunlight stimulates keratinocytes in the epidermis to release growth factors, such as stem cell factor, endothelin 1, alpha-melanocyte stimulating hormone (MSH), nerve growth factor — all are upregulated in melasma-affected areas. From the dermis, fibroblast growth factor and stem cell factor are upregulated. All of these cytokines are speaking to each other, and they’re upregulating pigment production in melanocytes.”
A Multimodal Treatment Approach
As a result, dermatologists should look at treating melasma through a multimodality lens, according to Dr. Grimes.
“We can’t be myopic and look at it from the perspective of just using a lightener. I think we have to approach it from the perspective of treating photodamaged skin, as well as reducing pigmentation,” she says.
That’s not to say that hydroquinone doesn’t have a role in melasma treatment.
Dr. Grimes receives grant/research/clinical trial support from: Galderma, Allergan/SkinMedica, Procter & Gamble, Clinuvel, Merz, Valeant, L’Oreal, Johnson & Johnson, Suneva, LaserOptek, VT Technologies, Incyte, Aclaris, Pfizer, Thync, and Dermaforce. She is a consultant/advisory board member for VT Technologies and Dermaforce.