Chapter 25: Melasma

INTRODUCTION

Melasma is an acquired brown macular hyperpigmentation usually of the face. It is far more common in females than in males. It usually presents bilaterally and symmetrically on the face, but extensor forearms may also be involved. There are believed to be three histologic variants of melasma: epidermal, dermal, and mixed dermal and epidermal. Epidermal melasma responds best to therapy. All forms have a high rate of recurrence, making this a frustrating condition to treat. Sun exposure, pregnancy, and oral contraceptive pills are all associated with its presentation and recurrence (Fig. 25.1).

EPIDEMIOLOGY

Incidence: common

Age: young females

Race: Central and South American, Middle Eastern, Indian, East Asian females are most frequently affected

Sex: females > males (9:1)

Precipitating factors: pregnancy, oral contraceptive pills, sun exposure, hormone replacement therapy

PATHOGENESIS

Unknown.

DERMATOPATHOLOGY

In epidermal melasma, there is increased melanin deposition in the epidermis, particularly in the basal and suprabasal layers. In dermal melasma, there are perivascular melanin-containing macrophages in the superficial and middermis. Mixed-type melasma exhibits features of each of the above findings.

PHYSICAL LESIONS

Patients present with well-demarcated light brown to dark brown symmetric macular hyperpigmentation. In approximately two-thirds of patients it appears on the central face including the forehead, nose, upper cutaneous lip, and chin. It presents less frequently on the malar areas and jawline. More rarely, it appears on the dorsal forearms. Dermal melasma has more of a blue-gray hue. Mixed-type melasma has a brown-gray coloration.

DIFFERENTIAL DIAGNOSIS

Postinflammatory hyperpigmentation, exogenous ochronosis, drug-induced/photo-hyperpigmentation, nevus of Ota, erythema dyschromicum perstans.

LABORATORY EXAMINATION

Wood’s lamp examination accentuates the increased epidermal pigmentation in melasma but does not highlight its dermal component.

COURSE

The pigmentation presents over a period of weeks. It occurs most commonly in summertime, with high estrogen states, during pregnancy, and prior to menstruation. It may fade completely months after delivery or after discontinuation of oral contraceptive pills. It may reappear in subsequent pregnancies and/or sun exposure.

KEY CONSULTATIVE QUESTIONS

• Medication history

• Pregnancy

• Sun exposure

• Time of onset

• Previous treatments

MANAGEMENT

There is no medical indication to treat melasma. Nevertheless, many patients understandably are distressed by its appearance and desire treatment. The goal of the treatment is to lighten or remove the pigmentation. Treating melasma can be quite frustrating. Prior to initiating therapy, it is essential for ...