PIH vs. Sun Damage: How to Treat UK Dark Spots | REFORM Skincare

You've noticed dark patches on your skin and you want them gone—but before you reach for the first brightening serum you find, there's a crucial question to answer: what kind of dark spots are you actually dealing with?

Not all hyperpigmentation is created equal. The two most commonly confused culprits are post-inflammatory hyperpigmentation (PIH) and sun damage (also called sunspots, age spots, or solar lentigines). They can look similar at first glance, but they form for entirely different reasons—and knowing which one you have determines which treatments will actually work.

Let's break down the science, spot the differences, and build a skincare strategy that targets your specific concerns.

What Is Post-Inflammatory Hyperpigmentation (PIH)?

PIH is your skin's way of leaving a receipt after inflammation. Whenever your skin experiences trauma—acne breakouts, eczema flare-ups, cuts, burns, aggressive treatments, or even insect bites—melanocytes (the cells that produce pigment) can go into overdrive as part of the healing response. The result? A flat, discoloured mark that lingers long after the original issue has healed.

Key Characteristics of PIH

• Cause: Inflammation or injury to the skin

• Appearance: Flat spots ranging from pink and red (in lighter skin tones) to brown, dark brown, or greyish-black (in deeper skin tones)

• Location: Wherever the original trauma occurred—commonly the face (from spots and blemishes), but can appear anywhere

• Behaviour: Temporary with proper care; fades over weeks to months, though deeper PIH can persist for years without treatment

• Who's affected: All skin tones, but PIH tends to be more pronounced and longer-lasting in medium to deep skin tones

The good news? PIH doesn't involve permanent structural damage to the skin. With patience and the right ingredients, these marks will fade.

What Is Sun Damage Hyperpigmentation?

Sun damage spots—often called sunspots, age spots, or solar lentigines—are the cumulative result of years of UV exposure. Unlike PIH, which follows a specific inflammatory event, sun damage builds up silently over decades. Every unprotected afternoon in the garden, every skipped sunscreen application, every drive with the sun hitting one side of your face—it all adds up.

When UV radiation hits your skin repeatedly, it damages melanocytes and disrupts how melanin is distributed. Over time, pigment accumulates unevenly, creating those characteristic brown spots that tend to appear in your 30s, 40s, and beyond.

Key Characteristics of Sun Damage

• Cause: Cumulative UV exposure over years or decades

• Appearance: Tan, brown, or dark brown spots; usually well-defined borders; can range from freckle-sized to over a centimetre in diameter

• Location: Sun-exposed areas—face, back of the hands, shoulders, forearms, chest, upper back

• Behaviour: Permanent and cumulative; won't fade on their own and tend to multiply with continued sun exposure

• Who's affected: More common and visible in lighter skin tones; risk increases with age and sun exposure history

Unlike PIH, sunspots don't resolve spontaneously. Without intervention, they stick around—and without sun protection, new ones continue to form.

How to Tell the Difference

Here's a quick diagnostic framework to help you identify what you're dealing with:

A practical test: Think back to what happened in that exact spot. Was there a pimple, a scratch, a burn, or a rash? If yes, it's likely PIH. If the spot appeared gradually in a sun-exposed area with no preceding event, you're probably looking at sun damage.

Treatment Strategies: Where They Overlap and Diverge

Both PIH and sun damage respond to many of the same ingredients—but your approach should differ based on the underlying cause.

Ingredients That Work for Both

• Vitamin C is a powerhouse for all types of hyperpigmentation. It inhibits tyrosinase (the enzyme that drives melanin production), neutralises free radicals from UV exposure, and brightens existing discolouration. For a potent daily dose, the REFORM Skincare Hyal Vitamin C+E Serum combines Vitamin C with Vitamin E and Ferulic Acid—a combination clinically shown to enhance stability and efficacy. The added Hyaluronic Acid ensures your skin stays hydrated while you brighten.

• Niacinamide (Vitamin B3) is another versatile player. It interrupts the transfer of melanin to skin cells, calms inflammation, and strengthens the skin barrier—making it particularly valuable for PIH, where ongoing inflammation can worsen pigmentation. REFORM Skincare formulations incorporate niacinamide to address multiple skin concerns simultaneously.

• Exfoliating acids (AHAs like glycolic and lactic acid) accelerate cell turnover, helping pigmented cells shed faster and revealing fresher skin beneath. They're effective for both conditions but require careful use—over-exfoliation can trigger new PIH, especially in sensitive or melanin-rich skin.

Tailoring Your Approach

For PIH:

Prevention is half the battle. Since PIH follows inflammation, your first priority is calming active breakouts or irritation before they leave marks. Gentle, non-stripping cleansers and barrier-supporting moisturisers reduce the inflammatory load on your skin.

Once PIH has formed, focus on:

• Gentle brightening ingredients (Vitamin C, niacinamide, arbutin)

• Mild exfoliation (start slow—once or twice weekly)

• Strict sun protection (UV exposure darkens PIH and extends its lifespan)

• Patience—PIH fades, but it takes time

Avoid aggressive peels or treatments that could re-traumatise the skin and trigger more PIH. This is one situation where gentleness wins.

For Sun Damage:

Sun damage is more stubborn than PIH and typically requires a more intensive approach:

• Consistent use of antioxidants (Vitamin C, Vitamin E, Ferulic Acid) to repair oxidative damage and prevent further accumulation

• Regular exfoliation to accelerate turnover of pigmented cells

• Retinoids to stimulate cell renewal and improve overall skin texture

• Professional treatments (chemical peels, laser therapy, IPL) for more significant sun damage

• Daily broad-spectrum SPF 30+—non-negotiable

The REFORM Skincare SPF30 Sunscreen uses Titanium Dioxide, a physical blocker that shields skin from UV rays without the irritation potential of some chemical filters. For anyone treating hyperpigmentation, this kind of protection isn't optional—it's foundational.

Building Your Routine

Here's a streamlined routine that addresses both types of hyperpigmentation while keeping your skin healthy and balanced:

Morning

1. Gentle cleanser – Remove overnight buildup without stripping

2. Vitamin C serum – Apply the REFORM Skincare Hyal Vitamin C+E Serum to clean, dry skin; let it absorb fully

3. Moisturiser – Hydration supports barrier function and healing

4. Sunscreen – REFORM Skincare SPF30 as the final step; reapply throughout the day if outdoors

Evening

1. Cleanser – Double cleanse if wearing sunscreen or makeup

2. Exfoliating acid (2–3 times weekly) – Glycolic or lactic acid to encourage turnover

3. Treatment serum – Niacinamide or a gentle retinol on alternate nights

4. Moisturiser – Lock in hydration and support overnight repair

The Non-Negotiable: Sun Protection

Whether you're dealing with PIH or sun damage, UV exposure makes everything worse. It darkens existing spots, triggers new melanin production, and undermines every brightening product you apply.

SPF isn't just for beach holidays. In the UK, even on grey, overcast days, UV rays penetrate cloud cover and windows, silently reaching your skin. Daily sunscreen—rain or shine, summer or winter—is the single most effective thing you can do to prevent hyperpigmentation from worsening or returning.

When to See a Professional

Most PIH and sun damage can be managed at home with consistent, targeted skincare. However, consult a GP or a consultant dermatologist if:

• Spots are changing in size, shape, or colour

• You notice any asymmetrical borders, itching, or bleeding

• You have a personal or family history of skin cancer

• Home treatments haven't shown improvement after 3–6 months

A specialist can provide a definitive diagnosis and recommend professional treatments like prescription retinoids, medical-grade chemical peels, or laser therapy for stubborn cases.

The Bottom Line

PIH and sun damage may look alike, but understanding their origins transforms how you treat them. PIH is inflammation's aftermath—temporary, responsive to gentle care, and preventable by managing breakouts and avoiding skin trauma. Sun damage is the long-term accumulation of UV exposure—persistent, requiring more targeted intervention, and only truly addressable with rigorous sun protection.

Both respond to brightening ingredients like Vitamin C and niacinamide. Both benefit from consistent exfoliation and antioxidant support. And both demand daily sunscreen as the foundation of any treatment plan.

With the right approach—and products formulated to deliver real results, like the REFORM Skincare range—clearer, more even-toned skin is absolutely within reach. The key is knowing what you're treating, staying consistent, and protecting your progress every single day.