Hormonal melasma is symmetrical, acquired hyperpigmentation driven by oestrogen-related stimulation of melanocyte activity. The combined oral contraceptive pill, hormone replacement therapy, and the hormonal fluctuation of perimenopause are the three most common triggers seen in aesthetic clinic populations. Understanding which trigger is active shapes the entire management plan, sets realistic expectations, and determines whether treatment holds or relapses within months of the first good result.
What Is Hormonal Melasma and Who Gets It?
Melasma is a common acquired pigmentary disorder that produces symmetrical brown or grey-brown patches, most often on the face. When the trigger is hormonal, the condition is sometimes referred to as chloasma, though the terms are used interchangeably in clinical literature. NICE CKS identifies the centrofacial and malar distribution patterns as most commonly associated with hormonal triggers, though the mandibular pattern also occurs.
The condition is far more common in women than in men, and is more prevalent in individuals with Fitzpatrick skin types III to VI, where melanocytes are more reactive to hormonal and UV stimulation. It is not purely a cosmetic concern for this group. At Fitzpatrick IV to VI, the pigmentation can be dense, persistent, and emotionally significant. It responds poorly to any treatment plan that does not first address the photoprotection foundation and, where possible, the hormonal driver.
Why Oestrogen Drives Melanocyte Activity
The mechanism is relatively well understood. Oestrogen binds to receptors on melanocytes, upregulating tyrosinase, the rate-limiting enzyme in the melanin synthesis pathway. This increases the rate at which melanocytes produce and transfer melanin to surrounding keratinocytes. The result is visible, diffuse hyperpigmentation in areas of highest sun exposure.
The key clinical implication is that oestrogen alone is rarely sufficient to produce melasma. UV exposure is almost always the co-trigger that activates the melanocyte in the context of an oestrogen-primed skin environment. This is why patients who have been on the combined pill for years will sometimes report that the pigmentation appeared only after a holiday. The oestrogen created the substrate; the UV flipped the switch.
It also explains the seasonal pattern: pigmentation tends to deepen through spring and summer, then lighten slightly over winter, but does not fully resolve, because the underlying melanocyte sensitivity remains.
The Combined Pill: The Most Common Iatrogenic Trigger
Combined oral contraceptives (those containing both oestrogen and progestogen) are the most frequent iatrogenic cause of melasma seen in aesthetic clinics. The oestrogen component, typically ethinylestradiol, is responsible. Progestogen-only pills and non-hormonal contraception are not associated with melasma in the same way.
The British Association of Dermatologists notes that melasma is a recognised side effect of the combined pill. Clinically, the pigmentation typically develops 3 to 6 months after starting the pill, though the timeline varies. Some patients notice it only after years of use and a period of increased UV exposure.
Two points to set with patients early:
First, stopping the pill does not guarantee resolution. Some patients see significant improvement within 6 to 12 months. Others retain residual pigmentation indefinitely. This needs to be framed honestly rather than as a promise. The melanocyte sensitivity that developed does not always fully reverse.
Second, stopping the pill is a decision for the patient's GP or prescribing clinician, not for an aesthetic practitioner. The practitioner's role is to document the suspected link, name it clearly in the consultation record, and encourage the patient to have a conversation with whoever prescribed it. A written note in the consultation summary, with the patient's consent, that identifies OCP as a probable trigger is appropriate and defensible.
HRT and Perimenopause: The Growing Clinical Picture
The second hormonal presentation that practitioners are seeing more frequently is melasma associated with HRT or with perimenopausal hormonal fluctuation. As the 40 to 55 demographic becomes a larger portion of aesthetic clinic populations, this presentation is worth understanding in detail.
In perimenopause, oestrogen levels do not simply fall. They fluctuate, often unpredictably, before declining overall. These fluctuations can stimulate melanocytes in the same way as exogenous oestrogen, and new melasma in a woman in her mid-to-late 40s with no history of OCP use is frequently perimenopausal in origin.
When HRT is added, the picture can shift in either direction. Transdermal oestrogen (patches, gel) has lower systemic absorption than oral oestrogen, and some practitioners and prescribing clinicians consider it to carry a lower melasma risk. The evidence for this distinction is not strong enough to treat it as certain, however. Any form of exogenous oestrogen can, in a susceptible individual, worsen existing melasma or trigger new onset. Practitioners should record the type and route of HRT in the consultation notes.
Again, the aesthetic practitioner's role is observation, documentation, and prompt communication. Modification of the HRT prescription is not within scope.
Photoprotection Is the Foundation, Not the Finishing Touch
No topical treatment for hormonal melasma works reliably without photoprotection. This is the single point that most treatment failures trace back to.
NICE CKS recommends broad-spectrum SPF 50 sunscreen applied daily to affected areas and reapplied every two hours when outdoors. In clinic populations with Fitzpatrick III to VI, there is additional reason to consider visible-light protection. Visible light, particularly in the 400 to 700 nm range, contributes to pigment deepening in this group, and standard chemical and mineral SPF does not fully block it. Iron-oxide-tinted sunscreens absorb visible light and are a more appropriate recommendation for patients with darker skin tones or those who spend time indoors under artificial lighting.
The practical conversation with a patient is straightforward: until she has SPF 50 on daily, consistently, with iron oxide if her Fitzpatrick type warrants it, the topical actives and any procedures you are considering have a lower ceiling. Set that expectation clearly, and make it part of the written aftercare.
Treatment Planning Within Scope
Once photoprotection is established and the hormonal trigger has been identified and communicated to the prescribing clinician, the aesthetic practitioner can work within a topical protocol. The agents with the strongest evidence base for hormonal melasma include:
- Tranexamic acid (topical and oral, where appropriate clinical governance exists): reduces melanin synthesis and has good tolerability across skin types
- Niacinamide: inhibits the transfer of melanosomes to keratinocytes, useful as a supporting agent
- Azelaic acid: tyrosinase inhibitor, also anti-inflammatory; licensed in the UK for acne and rosacea but used widely for pigmentation within practitioner scope
- Hydroquinone: effective but regulated; short-course use under clinical governance is appropriate for resistant cases
Peels, lasers, and microneedling carry a meaningfully higher risk of triggering post-inflammatory hyperpigmentation in patients with active melasma. Timing matters. Active, unstable melasma is not the right starting point for any procedure. Practitioners should wait for stabilisation, which typically means consistent photoprotection and topical treatment for at least 8 to 12 weeks before introducing a procedural element. Autumn and winter, when UV load is lower, are the preferred windows for procedural intervention.
Documenting the Hormonal Trigger
From a clinical governance perspective, the hormonal link needs to be in the record. This is not about liability avoidance for its own sake; it is about ensuring the patient's complete clinical picture is available to anyone who sees her subsequently, including her GP.
A clear consultation note might read: "Patient using combined OCP [name and dose]. Suspected hormonal trigger for melasma. Patient advised to discuss with GP. Discussed that resolution may be partial if OCP continues." Brief, factual, dated, signed. That is the standard.
If the patient declines to discuss OCP cessation or alternatives with her GP, that decision is hers to make. Document it and proceed with a treatment plan that acknowledges the ongoing trigger.
The full clinical framework behind hyperpigmentation assessment, including treatment sequencing, evidence review for each topical agent, and how to structure the consultation for this specific presentation, is inside Hyperpigmentation Decoded, the course built around the same NICE-aligned approach used in clinic. If you want a no-commitment first step, the free pigment quiz is a useful starting point to check where your knowledge currently sits.
FAQ
Is the combined pill the most common cause of melasma in women? Combined oral contraceptives are among the most frequent iatrogenic triggers for melasma in women of reproductive age. The oestrogen component drives melanocyte activity. Progestogen-only contraception does not carry the same risk. Not every patient on the combined pill develops melasma. Susceptibility appears linked to Fitzpatrick skin type and cumulative UV exposure.
Does melasma caused by the pill go away when you stop taking it? Not always. Improvement is common, particularly with consistent photoprotection after cessation, but some patients retain residual pigmentation for years. Practitioners should set realistic expectations at the first consultation rather than implying that stopping the pill will resolve the pigmentation completely.
Can UK aesthetic practitioners treat hormonal melasma? Yes, within scope. Photoprotection advice, topical depigmenting agents, and appropriately timed procedures are all within aesthetic scope. Managing or advising on the hormonal trigger itself (OCP or HRT decisions) is not, but practitioners can and should document the suspected trigger and encourage the patient to discuss it with their GP.
Is perimenopause associated with new-onset melasma? Yes. The hormonal fluctuation of perimenopause can stimulate melanocytes in the same way as exogenous oestrogen. New-onset melasma in a woman in her mid-to-late 40s with no history of OCP use is frequently perimenopausal in origin. HRT, if initiated, can either stabilise or worsen the picture depending on the formulation and the individual.
Why does melasma worsen in summer? UV exposure acts as the co-trigger that activates melanocyte activity in the context of an oestrogen-primed skin environment. Even with consistent topical treatment, inadequate photoprotection in high-UV months will deepen the pigmentation. Iron-oxide-tinted SPF 50 applied daily and reapplied at midday is the minimum standard for active melasma management.
Should aesthetic practitioners advise patients to stop the pill? No. That decision sits with the patient's GP or prescribing clinician. The aesthetic practitioner's role is to identify the probable link, document it in the consultation record, and communicate clearly with the patient about the likely impact of continuing the trigger on treatment outcomes. The conversation is appropriate; the decision is not the practitioner's to make.