Hyperpigmentation disorders

Hyperpigmentation is an increase in melanin in the epidermis and/or dermis. Hyperpigmentation disorders are benign conditions that manifest with lesions that are darker than the adjacent skin. Causes of hyperpigmentation disorders include genetic or medical conditions and exposure to UV radiation. A detailed patient history and skin examination are required to establish the lesion type. In cases of diagnostic uncertainty, further workup may include skin biopsy and dermatologist evaluation (e.g., with Wood lamp). The general management of hyperpigmentation disorders involves using photoprotective measures and addressing underlying conditions if necessary. If requested by the patient, cosmetic treatment with skin lightening therapy may be performed.

• Description: a benign type of hyperpigmentation with onset typically during childhood ^[1]
• Etiology: genetic; precipitated by UV exposure ^[1][2]
• Epidemiology ^[1]
  • Prevalence is higher among children ≥ 2 years of age and subsequently decreases with age. ^[3]
  • Predominantly affects individuals with light skin
• Clinical features ^[1][3]
  • Well-defined macules of varied color (red, brown, or tan)
  • 1–2 mm in size
  • Number can vary from a few to hundreds
  • Typically located in sun-exposed areas
• Differential diagnosis ^[1]
  • Juvenile lentigo
  • Solar lentigo
• Management: See “Management of hyperpigmentation disorders.” ^[1][4]

Ephelides fade with reduced sun exposure in the winter months. ^[1][2]

• Description: an acquired type of hyperpigmentation that affects adults ^[1]
• Etiology: exposure to UV radiation ^[1]
• Epidemiology
  • Prevalence is highest in adults > 40 years. ^[5]
  • Predominantly affects individuals with light skin and Asian individuals ^[1]
• Pathophysiology: increase in the production of melanin, which is then deposited in basal keratinocytes
• Clinical features ; ^[1]
  • Yellow or brown macules or patches
  • Typically located on sun-exposed areas (e.g., face, back of the hands)
  • Number increases with age. ^[2]
• Differential diagnosis ^[1][6]
  • Ephelides
  • Seborrheic keratosis
  • Actinic keratosis
  • Lentigo maligna
  • Melanoma
• Management: See “Management of hyperpigmentation disorders.” ^[1]

• Description: : a benign type of hyperpigmentation with onset commonly at birth or in childhood ^[1][3]
• Etiology: idiopathic or genetic (e.g., neurofibromatosis, McCune-Albright syndrome) ^[1][3]
• Epidemiology: isolated finding in 10–30% of the general population ^[1][3]
• Clinical features ^[1][3]
  • Well-defined tan or brown macule or patch
  • 1–20 cm in size ^[1][3]
  • Idiopathic lesions are typically solitary.
  • ≥ 6 lesions suggest a genetic syndrome. ^[1]
• Differential diagnosis ^[7]
  • Becker nevus
  • Urticaria pigmentosa
• Management ^[1][3][4]
  • See “Management of hyperpigmentation disorders.”
  • If there is concern for a genetic syndrome such as neurofibromatosis or McCune-Albright syndrome, , refer to a specialist.

• Description: an acquired type of hyperpigmentation occurring on sun-exposed areas ^[3][8]
• Etiology ^[1][3]
  • Exposure to UV radiation
  • Hormonal factors, e.g.:
    • Pregnancy: referred to as “mask of pregnancy” ^[9]
    • Oral contraceptive use
  • Medications (e.g., anticonvulsant drugs)
• Epidemiology ^[1][3]
  • Common in individuals with dark skin
  • Incidence: ♀ > ♂
• Clinical features ^[1][3]
  • Macules or patches of varied color (e.g., brown or grey)
  • Usually on the face (centrofacial, malar, or mandibular pattern) or forearms and bilateral
• Differential diagnoses ^[7]
  • Actinic lichen planus
  • HIV-associated dermatological complications
  • Contact dermatitis (caused by, e.g., cosmetics)
• Management ^[1][4][8]
  • See “Management of hyperpigmentation disorders.”
  • Wood lamp can show skin enhancement for lesions with an epidermal component.
  • Treatment resistance is common; refer to a dermatologist for further management. ^[1]

Melasma usually recurs after treatment is discontinued, but it may be self-limiting in pregnant individuals, resolving in the postpartum period. ^[1][9]

• Description: an acquired type of hyperpigmentation that results from injury, inflammation, or procedures ^[1]
• Etiology ^[1][3][10]
  • Exposure to sunlight or UV radiation
  • Preceding skin conditions
    • Primary or secondary photodermatoses
    • Inflammatory (e.g., atopic dermatitis, acne)
    • Infectious (viral, bacterial, or fungal)
  • Injury (e.g., abrasion)
  • Iatrogenic (e.g., radiation, dermatological procedures)
  • Hypersensitivity reactions
  • Malignancy (i.e., mycosis fungoides)
• Epidemiology: predominantly affects individuals with dark skin ^[1][3]
• Clinical features ^[1][10]
  • Irregular macules or patches of varied color depending on lesion depth, e.g., tan to dark brown for epidermal lesions, blue-gray for dermal lesions. ^[3]
  • Location depends on the underlying cause. ^[1]
• Management ^[1][4][10]
  • Treat the underlying cause, if possible (e.g., treatment of atopic dermatitis, treatment of acne by severity). ^[3]
  • See also “Management of hyperpigmentation disorders.”

Postinflammatory hyperpigmentation can persist for months to years, especially if the underlying cause is not addressed or the lesion extends to the dermis. ^[1][3]

Diagnostics ^[1][3][5]

• Hyperpigmentation disorders are usually a clinical diagnosis.
• Cases of diagnostic uncertainty
  • Perform a skin biopsy to confirm excess melanin and/or rule out malignancy, if suspected.
  • Refer to a dermatologist if further diagnostics are needed to confirm the diagnosis (e.g., Wood lamp for melasma).

Perform a skin biopsy to rule out melanoma in patients with lesions that meet ABCDE critieria. ^[1]

Treatment ^[4]

Treatment is generally not necessary for hyperpigmentation disorders.

• Advise all patients to use photoprotective measures.
• Address any underlying conditions, if applicable (e.g., acne associated with postinflammatory hyperpigmentation).
• For patients who desire cosmetic treatment:
  • Suggest the use of cosmetics to cover areas of concern.
  • Consider dermatologist referral for skin lightening therapy.

Photoprotective measures can prevent new or worsening hyperpigmentation and lighten existing areas of hyperpigmentation. ^[4]

Skin lightening therapy ^[4]

Treatment options are often used in combination and selected based on lesion type, skin tone, and patient preference.

• Topical pharmacotherapy
  • Preferred: hydroquinone or a combination of hydroquinone, retinoid, and corticosteroid ^[4]
  • Alternatives include azelaic acid, ascorbic acid, niacinamide.
• Systemic pharmacotherapy
  • Often used if there is an insufficient response to topical pharmacotherapy
  • Example: oral tranexamic acid
• Procedural therapy
  • Often used for cases refractory to topical and systemic pharmacotherapy
  • Examples: chemical peels, laser or light therapy, cryotherapy

Continuous use of hydroquinone for more than approx. 3–6 months is not recommended because of the risk of adverse effects (e.g., postinflammatory hyperpigmentation, skin irritation). ^[4]

Some treatments for hyperpigmentation disorders are not recommended during pregnancy or breastfeeding because of insufficient evidence of their safety. ^[4]