Hyperpigmentation

Melasma consists of dark brown, roughly symmetric patches of hyperpigmentation with irregular borders on the face (usually on the forehead, temples, cheeks, cutaneous upper lip, or nose). It occurs primarily in pregnant women (melasma gravidarum, also called the mask of pregnancy) and in women taking oral contraceptives Oral Contraceptives Oral contraceptives (OCs) mimic ovarian hormones. Once ingested, they inhibit the release of gonadotropin-releasing hormone (GnRH) by the hypothalamus, thus inhibiting the release of the pituitary... read more . Ten percent of cases occur in nonpregnant women and dark-skinned men. Melasma is more prevalent among and lasts longer in people with dark skin.

Because melasma risk increases with increasing sun exposure, the mechanism probably involves overproduction of melanin by hyperfunctional melanocytes. Other than sun exposure, aggravating factors include

In women, melasma fades slowly and incompletely after childbirth or cessation of hormone use. In men, melasma rarely fades.

The mainstay of melasma management is strict photoprotection agents. Patients should use sunscreen with a sun protection factor (SPF) of 30 or higher, wear protective clothing and hats, and avoid direct sun exposure. During and after therapy, strict sun protection must be maintained. Because visible light is not blocked by most sunscreens, patients should use a tinted sunscreen (eg, that contains zinc oxide or titanium dioxide). The addition of antioxidants to the sunscreen and oral adjunctive photoprotection agents such as Polypodium leucotomas can enhance protection (1 Melasma references Hyperpigmentation has multiple causes and may be focal or diffuse. Most cases are due to an increase in melanin production and deposition. (See also Overview of Pigmentation Disorders.) Focal... read more , 2 Melasma references Hyperpigmentation has multiple causes and may be focal or diffuse. Most cases are due to an increase in melanin production and deposition. (See also Overview of Pigmentation Disorders.) Focal... read more ). Because of potential health and environmental toxicities, oxybenzone and benzophenone-3 are usually not preferred sunscreens (3 Melasma references Hyperpigmentation has multiple causes and may be focal or diffuse. Most cases are due to an increase in melanin production and deposition. (See also Overview of Pigmentation Disorders.) Focal... read more ).

Other treatment depends on whether the pigmentation is epidermal or dermal; epidermal pigmentation becomes accentuated with a Wood light Wood light Diagnostic tests are indicated when the cause of a skin lesion or disease is not obvious from history and physical examination alone. These include Patch testing Biopsy Scrapings Examination... read more (365 nm) or can be diagnosed with biopsy. Only epidermal pigmentation responds to treatment. Most topical melasma treatments are used in combination rather than individually.

Triple topical therapy is first-line treatment that is often effective and consists of a combination of

Hydroquinone depigments the skin by blocking the enzymatic oxidation of tyrosine 3,4-dihydroxyphenylalanine (DOPA) and inhibiting melanocyte metabolic processes. Hydroquinone should be tested behind one ear or on a small patch on the forearm for 1 week before use on the face because it may cause irritation or an allergic reaction. Tretinoin promotes keratinocyte turnover and can exfoliate skin that contains epidermal pigment. Corticosteroids help block synthesis and secretion of melanin. Two promising technologies being tried in conjunction with triple topical therapy are the Q-switched Nd:YAG (1064 nm) laser and nonablative fractional resurfacing.

If triple topical therapy is not available, then hydroquinone 3 to 4% applied twice a day for up to 8 weeks at a time (chronic continuous use can theoretically increase the risk of exogenous ochronosis, which is a permanent form of hyperpigmentation) may be considered; 2% hydroquinone is useful as maintenance.

Azelaic acid 15 to 20% cream can be used in place of or with hydroquinone and/or tretinoin. Azelaic acid is a tyrosinase inhibitor that reduces melanin production. In addition, topical kojic acid has been increasingly used; it is a chelating agent that blocks tyrosine conversion to melanin.

During pregnancy, azelaic acid 15 to 20% cream and chemical peeling with glycolic acid are safe to use. Hydroquinone and tretinoin are not safe to use.

Second-line treatment options for patients with severe melasma unresponsive to topical bleaching agents include chemical peeling with glycolic acid or 30 to 50% trichloroacetic acid. Laser treatments also have been used but are not standard therapy.

Oral therapies have been studied. A randomized study has shown improvement with oral tranexamic acid in patients with moderate-to-severe melasma (4 Melasma references Hyperpigmentation has multiple causes and may be focal or diffuse. Most cases are due to an increase in melanin production and deposition. (See also Overview of Pigmentation Disorders.) Focal... read more ).

Lentigines (singular: lentigo) are flat, tan to brown, oval macules. They are commonly due to chronic sun exposure (solar lentigines; sometimes called liver spots but are not related to hepatic dysfunction) and occur most frequently on the face and back of the hands. They typically first appear during middle age and increase in number with age. Although progression from lentigines to melanoma has not been established, lentigines are an independent risk factor for melanoma Melanoma Malignant melanoma arises from melanocytes in a pigmented area (eg, skin, mucous membranes, eyes, or central nervous system). Metastasis is correlated with depth of dermal invasion. With spread... read more .

If lentigines are a cosmetic concern, they are treated with cryotherapy or laser; hydroquinone is not effective.

Nonsolar lentigines are sometimes associated with systemic disorders, such as Peutz-Jeghers syndrome Peutz-Jeghers Syndrome Peutz-Jeghers syndrome is an autosomal dominant disease with multiple hamartomatous polyps in the stomach, small bowel, and colon along with distinctive pigmented skin lesions. Most (66 to 94%)... read more (in which profuse lentigines of the lips occur), multiple lentigines syndrome (or LEOPARD syndrome, which stands for multiple Lentigines, Electrocardiogram [ECG] conduction abnormalities, Ocular hypertelorism, Pulmonic stenosis, Abnormal genitals, Retardation of growth, and sensorineural Deafness), or xeroderma pigmentosum.

Changes are usually diffuse but sometimes have drug-specific distribution patterns or hues ( see Table: Hyperpigmentation Effects of Some Drugs and Heavy Metals Hyperpigmentation Effects of Some Drugs and Heavy Metals ). Mechanisms include

Drugs may cause secondary hyperpigmentation. For example, focal hyperpigmentation frequently occurs after drug-induced lichen planus Lichen Planus Lichen planus is a recurrent, pruritic, inflammatory eruption characterized by small, discrete, polygonal, flat-topped, violaceous papules that may coalesce into rough scaly plaques, often accompanied... read more (also known as lichenoid drug eruption).

In fixed drug eruptions, red plaques or blisters form at the same site each time the causative drug is taken; residual postinflammatory hyperpigmentation usually persists, especially in darker skin types. Typical lesions occur on the face (especially the lips), hands, feet, and genitals. Typical inciting drugs include antibiotics (sulfonamides, tetracyclines, trimethoprim, and fluoroquinolones), nonsteroidal anti-inflammatory drugs, and barbiturates.

Treatment of drug-induced hyperpigmentation involves stopping the causative drug; the hyperpigmentation fades very slowly in some if not all cases. Because many drugs that cause skin pigmentation also cause photosensitivity reactions Photosensitivity Photosensitivity is a cutaneous overreaction to sunlight. It can be related to photoallergy or phototoxicity and may be idiopathic or occur after exposure to certain toxic or allergenic drugs... read more , patients should avoid sun exposure Prevention The skin may respond to sunlight with chronic (eg, dermatoheliosis [photoaging], actinic keratosis) or acute (eg, photosensitivity, sunburn) changes. The sun emits a wide range of electromagnetic... read more .