Synopsis
Distinguish patterned melasma from pigment left by inflammation, identify atypical or iatrogenic causes, and use slow, low-irritancy treatment that does not intensify dyschromia.
- Melasma causes acquired symmetrical brown or grey-brown facial patches, commonly centrofacial or malar, influenced by ultraviolet and visible light, hormones and genetic susceptibility.
- Post-inflammatory hyperpigmentation follows eczema, acne, infection, trauma, procedures or irritation and mirrors the sites and shapes of the preceding inflammatory process.
- Both are more visible and often more persistent in richly pigmented skin; this reflects melanin biology and treatment response, not poor hygiene or inadequate care.
- Take a timeline covering pregnancy, contraception, medicines, cosmetics, occupational exposure, inflammation and procedures before adding a pigment treatment.
- Treat active dermatitis or acne first and use broad-spectrum photoprotection; repeated irritation from scrubs, peels or multiple active products creates more pigment.
- Epidermal brown pigment generally improves faster than dermal blue-grey pigment, but Wood-lamp depth prediction is imperfect, particularly in darker skin.
- Topical azelaic acid is an off-label pigment option with a favourable reproductive safety profile; hydroquinone and retinoid combinations require specialist oversight and strict pregnancy discussion.
- Set expectations in months, not days. Relapse of melasma is common, and residual pigment can outlast successful control of the original inflammation.
Key red flags
A single changing irregular pigmented lesion, mucosal or nail pigmentation, bleeding, ulceration, palpable infiltration, systemic illness or rapid unexplained diffuse pigmentation requires prompt diagnostic assessment rather than empirical lightening treatment.
Investigation priorities
Separate patterned melasma, inflammatory pigment and an exposure-related reaction.
Management branches
Facial or localised hyperpigmentation is the presenting concern.
- Map distribution and colour, examine surface and compare current pigment with photographs and the shape of any preceding inflammatory eruption.
- Review pregnancy, hormonal contraception, systemic and topical medicines, cosmetics, peels, friction and occupational light or chemical exposure.
- Use dermoscopy and selective Wood-lamp examination, then biopsy or refer any solitary evolving, indurated, ulcerated or otherwise atypical lesion before applying a lightener.
Key medicines
Azelaic acid 20% creamApply a thin layer to affected facial skin twice daily after gentle cleansing; reduce to once daily or pause briefly if irritation is troublesome.Explain that pigmentation is an off-label indication. Avoid eyes and mucosa, introduce gradually on reactive skin and stop significant burning or dermatitis; improvement requires sustained use over months.
Hydroquinone specialist pigment treatmentUse only the dermatologist-selected unlicensed or compounded concentration, often once nightly for a strictly time-limited course with a documented stop date.Avoid pregnancy and breastfeeding unless a specialist determines otherwise; monitor irritant dermatitis and paradoxical exogenous ochronosis, and never obtain high-strength mixtures from unregulated sellers.