Melasma in Pregnancy

Acquired symmetrical hypermelanosis of the face, also called chloasma or the mask of pregnancy. It affects about 50 to 70% of pregnant women, and is more frequent in women with skin types III to V (Hispanic, Asian, Middle Eastern, African and Mediterranean ancestry).

• Pathogenesis: increased melanocyte activity under the effect of oestrogen, progesterone and melanocyte stimulating hormone, with ultraviolet and visible light as the necessary trigger. Genetic predisposition (a family history in about 40%), thyroid autoimmunity, and some cosmetics and drugs (oestrogen containing contraceptives, phenytoin, photosensitising agents) contribute.
• Onset is usually in the second or third trimester, and darkening increases with advancing pregnancy and sun exposure.
• Most patches fade over 3 to 12 months after delivery. About 30% persist for years, and recurrence in later pregnancies or with oestrogen containing contraceptives is common.
• Types by depth: epidermal (brown, enhanced under Wood lamp, responds best to treatment), dermal (grey blue, not enhanced, poor response), and mixed.

• Symmetrical light to dark brown, irregular, well demarcated macules and patches on the face. Patterns: centrofacial (forehead, cheeks, nose, upper lip, chin; the commonest), malar (cheeks and nose), and mandibular.
• No scale, itch or symptoms. Other pregnancy related pigmentation (darkening of the nipples, areolae, linea nigra, genital skin, and freckles) is often present.
• Differential diagnosis: post-inflammatory hyperpigmentation, drug induced pigmentation (minocycline, amiodarone, phenytoin, hormonal contraceptives), Riehl melanosis (contact allergen), acquired bilateral naevus of Ota like macules (blue grey), solar lentigines, lupus erythematosus (malar rash with scale and photosensitivity), ochronosis from hydroquinone, actinic lichen planus, Addison disease (generalised, with mucosal and palmar crease pigmentation), thyroid disease, and acanthosis nigricans.
• Complications: psychological distress, reduced quality of life, and persistence after pregnancy.

• Clinical. Ask about onset in relation to pregnancy, sun exposure, previous episodes, family history, contraceptives and drugs, and cosmetics.
• Wood lamp and dermoscopy help type the depth. Biopsy is rarely needed and shows increased melanin in the epidermis, with or without dermal melanophages.
• If the patient has other features (fatigue, weight loss, hypotension, salt craving, widespread or mucosal pigmentation, goitre, or symptoms of thyroid disease), check morning cortisol, thyroid function and antibodies.
• Consider antinuclear antibody and other tests if lupus is suspected.

• During pregnancy and lactation, treatment is limited to safe measures. Reassure the patient that most pigmentation fades after delivery.
• Photoprotection is the core of treatment, since light drives the disease:
  • Broad spectrum sunscreen SPF 50 or more, applied thickly every morning and reapplied every 2 hours when outdoors. Mineral sunscreens (zinc oxide, titanium dioxide) are preferred in pregnancy.
  • Choose a tinted product containing iron oxides, which also blocks visible light and works better than untinted products.
  • Wide brimmed hat, sunglasses, shade, and avoidance of peak sun and of heat exposure, which also worsens melasma.
  • Gentle skin care: avoid irritants and waxing of facial skin.
• Treatments considered safe in pregnancy:
  • Azelaic acid 15% gel or 20% cream, twice daily for 3 to 6 months. It is safe in pregnancy and lactation, and may sting transiently.
  • Camouflage makeup.
• Avoid during pregnancy: hydroquinone (systemic absorption is about 35 to 45% and safety data are limited), tretinoin and all retinoids (contraindicated), the triple combination cream (hydroquinone, tretinoin and a steroid), oral tranexamic acid (thrombotic risk), chemical peels, lasers, and kojic acid.
• After delivery (and, for most agents, after breastfeeding), if pigmentation persists for 3 to 6 months:
  • Hydroquinone 2 to 4% cream, applied twice daily to the patches for 8 to 12 weeks, then stopped or reduced to avoid exogenous ochronosis (blue black discolouration) and irritation.
  • The triple combination cream (hydroquinone 4%, tretinoin 0.05%, fluocinolone acetonide 0.01%) nightly for 8 weeks, then a maintenance regimen of 2 to 3 times weekly. Avoid while breastfeeding.
  • Azelaic acid 15 to 20% twice daily, which can be combined with the other topical agents listed here.
  • Cysteamine 5% cream daily, or topical vitamin C (L-ascorbic acid 10 to 20%), or niacinamide 4 to 5%, as adjuncts.
  • Oral tranexamic acid 250 mg twice daily (or 325 mg twice daily) for 3 months, then reduce, in specialist care. It is contraindicated in women with a history of venous thromboembolism, thrombophilia, cardiovascular disease, or who take oestrogen containing contraceptives, and the dose is reduced in renal impairment. It should not be used in pregnancy, and data in breastfeeding are limited.
  • Superficial chemical peels (glycolic acid 20 to 50% or salicylic acid 20 to 30%) every 2 to 4 weeks, for 3 to 6 sessions. Avoid deep peels.
  • Low fluence Q-switched Nd:YAG 1064 nm laser, picosecond laser or fractional non-ablative laser, by experienced operators, since heat and inflammation can cause rebound pigmentation (more in dark skin).
• Stop oestrogen containing contraceptives and hormone therapy if melasma persists, and use a progestogen only or non-hormonal method.
• Special groups:
  • Dark skin: use gentle regimens with sunscreen, avoid aggressive lasers and peels, and watch for irritation, which causes post-inflammatory pigmentation.
  • Women planning another pregnancy: warn about recurrence and continue strict photoprotection.
  • Lactation: azelaic acid and sunscreen are suitable. Avoid retinoids and tranexamic acid.
• Follow up: review at 6 to 12 weeks after delivery. Refer to dermatology for persistent disease, dermal melasma, or procedure based treatment.