Using hue and history to distinguish facial pigmentation disorders…

Facial pigmentation is a common concern in general practice, often driven by cosmetic awareness and anxiety about progressive discolouration. While many patients present with what they believe to be “melasma”, a careful clinical approach often reveals a broader differential diagnosis.

A colour-focused, structured assessment can help GPs distinguish between common causes of facial pigmentation and initiate appropriate, pragmatic management.

Start with colour

As in many areas of dermatology, colour is an important diagnostic clue. Not all pigmentation is simply “brown”, and subtle variation in hue can help determine both diagnosis and treatment responsiveness.

Warm coffee-brown tones imply epidermal pigment, commonly seen in solar lentigines or epidermal melasma. Cool slate-grey or blue-grey hues, by contrast, suggest dermal pigment or contact-induced melanosis, seen in dermal melasma, pigmented contact dermatitis (Riehl’s melanosis) or Hori’s nevus in Asian skin. Recognising this distinction in colour variation early helps avoid prolonged use of topical lightening agents in conditions unlikely to respond.

Practice tip: colour as a diagnostic shortcut
Brown pigmentation points to epidermal involvement, which is often responsive to topical therapy. Grey or blue-grey suggests dermal melasma or pigmented contact dermatitis, which may require a multi-step therapeutic approach.

Pattern recognition and common presentations

In Australia, solar lentigines are extremely common on chronically sun-exposed skin and appear as discrete brown macules against a background of photodamage. Melasma, however, follows a symmetrical pattern typically across the malar cheeks, forehead or upper lip, and is strongly influenced by hormonal change and UV exposure.

In patients of Asian background or those with darker skin types, Hori’s nevus should be considered when there is bluish periorbital and malar pigmentation. Meanwhile, in patients reporting progressive, diffuse facial pigmentation, especially with a history of multiple skincare products followed by sun exposure, consider pigmented contact dermatitis, even in the absence of visible inflammation.

History: powerful diagnostic tool in dermatology

In facial pigmentation, a well-structured history often provides strong diagnostic clarity.

Ask specifically about:

Skincare and cosmetic use

• Number of products used (AM/PM), order of application and whether applied immediately before sun exposure
• Prescence of fragrance, preservatives or “brightening” actives; common triggers for pigmented contact dermatitis

Trigger patterns

• Gradual onset following new product introduction is suggestive of pigmented contact dermatitis
• Recurrent flares with sun or hormonal changes are more consistent with melasma

Hormonal influences

• Pregnancy or use of oral contraceptives/hormone therapy support melasma

Ethnic background

• For people with an Asian background consider Hori’s nevus
• In people with skin of colour, post-inflammatory pigmentation may appear without visible erythema, making lupus or dermatitis less obvious

Practice tip: Many patients present with a self-diagnosis of “melasma”. Reassess when pigmentation is grey rather than brown, diffuse rather than sharply edged, or when there is a history of new cosmetic routines.

Management: reset before treating

Management should begin with simplifying the skincare routine. Advise patients to stop unnecessary serums, toners and fragranced products, and instead use bland, fragrance-free, soap-free moisturisers. Sun protection is essential, with preference for mineral-based sunscreens to minimise irritation or photosensitivity.

Targeted treatment should only be introduced after potential triggers have been reduced. Hydroquinone (2–4%), kojic acid and tretinoin are the most evidence-based topical options, often compounded together into a combination therapy. These agents should be started slowly, typically a few nights a week before progressing to nightly application if tolerated. Advise patients that improvement is gradual, often taking three months before meaningful change is visible. Photographic documentation at baseline and review helps reinforce progress and improve adherence.

For deeper, dermal pigmentation, particularly melasma unresponsive to topical therapy, oral tranexamic acid can be considered. It is prescribed at 250 mg twice daily, but only after screening for protein C and S deficiency, as thrombotic risk must be excluded. Again, patients should be counselled that results take time, with at least three months of therapy recommended before reassessment.

Procedural options

Chemical peels provide a middle-tier intervention and are relatively accessible, usually costing around $100–200 per session, with three to six treatments spaced monthly.

Q-switched Nd:YAG and picosecond lasers are options for both epidermal and dermal pigmentation. They fragment pigment particles but require multiple sessions and substantial financial investment. While microneedling is traditionally considered a treatment for photoaging rather than pigmentation, current evidence suggests that it is improvement in the extracellular matrix and collagen remodelling that can also improve the appearance of pigmentation especially in the context of melasma.

When to biopsy

Melasma is a clinical diagnosis and does not usually require biopsy. However, if the pigmentation is atypical, associated with erythema, scale or textural change, or if systemic features such as hair loss or mucosal involvement are present, biopsy should be considered.

Biopsy may also be appropriate in suspected pigmented contact dermatitis when pigmentation is progressive, grey in tone, arises in the context of multiple cosmetic products applied before sun exposure, and the pattern does not resemble classic melasma, particularly when the diagnosis is not clear on clinical grounds alone.

When to refer

Referral to dermatology is appropriate when the diagnosis is uncertain, systemic features suggest autoimmune conditions, or when laser treatment or biopsy is being considered. It is also reasonable to seek specialist input if pigmented contact dermatitis is suspected and patch testing or histology is not readily accessible in general practice.

Key takeaways

• Identify the likely pigment depth based on colour. Brown pigment suggests epidermal origin; grey or blue-grey suggests dermal or contact pigmentation.
• Always review cosmetic and skincare habits; sun exposure after product use is a key clue for pigmented contact dermatitis.
• Melasma takes months to respond to treatment so set expectations early.
• Start by removing triggers and simplifying skincare before initiating topical or systemic therapies.
• Refer when pigmentation is atypical, symptomatic, dermal and resistant, or when biopsy or laser is being considered.

Dr Philip Tong is a Sydney-based dermatologist and founder of DermScreen, a telehealth platform that supports GPs with dermatology-related clinical decision making. He offers nation-wide telehealth services for medical dermatology including acne, eczema and psoriasis through his clinic Dermatology Junction.