Persons with Fitzpatrick skin types III-VI and those of certain ethnic groups tend to have a higher risk of darker pigmentation on certain parts of the body. Melasma, postinflammatory hyperpigmentation, and lentigines often respond to treatment with topical antipigment agents, chemical peels, and lasers. Darker pigment on the elbows and knees, if bothersome also can be treated with topical antipigment creams, plus or minus topicals that promote exfoliation (such as urea-based topicals). If the skin is acanthotic on elbows or knees, a topical steroid can be used first to thin the area before applying a lightening agent.
But what about pigmentation of the eyelids, axillae, and neck? At these thinner, more sensitive areas of skin, the cause of darker pigment could be multifactorial. Treatment can be difficult because the same methods we use to treat pigmentation in other areas can be too aggressive for these locations. A recent study by Saedi and Ganesan (J. Drugs Dermatol. 2013;12:563-7) surveyed practicing dermatologists’ methods of treating hyperpigmentation of the eyelids, axillae, and neck. Fifty dermatologists completed the survey, and 46 (92%) reported treating patients with darker skin. The ethnic groups treated included Hispanic (97.8%), black (97.8%), Middle Eastern (77.6%), and Asian (88.9%). Thirty-six survey respondents reported treating patients with hyperpigmentation under the eyes, and 22 (61.1%) thought the hyperpigmentation was a result of idiopathic increase in melanin deposition. Forty-two responded to treating hyperpigmentation in the axilla, most of whom thought it was related to acanthosis nigricans (69.0%) or contact dermatitis (59.5%). Forty responded to treating hyperpigmentation on the neck, most of whom treated the condition with hydroquinone (66%). Treatments for these three areas were not found to be effective.
Pigment in these areas could be normal and purely genetic, such as variations in skin pigment because of embryonic pigment demarcation areas, versus an underlying pathology.
For the eyelids, that pathology could include increased pigment from inflammatory conditions (eczema, allergies, allergic or irritant contact dermatitis, photodermatitis), autoimmune conditions (dermatomyositis, lupus), medications (bimatoprost, among others), heavy metal poisoning (colloidal silver, lead, mercury), or increased vascularity. Treating these underlying conditions may help improve the appearance of darker eyelids. Hyperpigmentation treatment options include a series of light chemical peels, topical lightening agents such as kojic acid, and resurfacing lasers, but caution must be taken to avoid additional postinflammatory pigmentation from these procedures. Long-term sun protection and sunscreen use is imperative in any area after treatment.
Tear trough deformity because of volume loss under the eyes also can cause the appearance of darker lower eyelids. However, hyperpigmentation of the skin is not the primary issue in these cases, and the appearance can often improve with placement of dermal fillers.
For the axillae and neck, conditions that could promote hyperpigmentation include postinflammatory pigmentation (caused by irritant or allergic contact dermatitis, infection, waxing, or friction), UV exposure, acanthosis nigricans, and photodermatitis, especially from photosensitizing medications. All of these conditions may also respond to topical antipigment ingredients and attention to the underlying condition, but unfortunately, not always to the patient’s greatest satisfaction.
What are your strategies for hyperpigmentation on the tough-to-treat areas of the eyelids, neck, or axillae?
Dr. Wesley practices dermatology in Beverly Hills, Calif.
Do you have questions about treating patients with dark skin? If so, send them to sknews@frontlinemedcom.com.