Post-Acne Dark Marks vs Red Marks (PIH vs PIE): How to Tell and Treat Them

When a pimple heals, it often leaves a flat mark behind. Some marks are brown, while others stay pink or red for months. These look similar at first glance, but they are two different problems. Brown marks are post-inflammatory hyperpigmentation (PIH), and red marks are post-inflammatory erythema (PIE). Because each has a different cause, each needs a different treatment. If you are unsure which marks you have, you can contact CLEO Clinic to have a doctor check your skin.

What Is PIH (Post-Inflammatory Hyperpigmentation)?

PIH is a flat brown, dark brown or grey-brown mark left after inflammation in the skin. In acne, the inflammation triggers melanocytes to produce extra melanin, which stays behind after the pimple has gone. Notably, PIH is very common in Asian and darker skin tones, because these skin types produce pigment more readily after irritation. In addition, picking, squeezing and sun exposure make PIH darker and slower to fade.

What Is PIE (Post-Inflammatory Erythema)?

PIE is a flat pink, red or purplish mark that remains after acne heals. Unlike PIH, it is not caused by pigment. Instead, it comes from small, dilated blood vessels near the surface of the skin. A 2023 study in Clinical, Cosmetic and Investigational Dermatology describes post-acne erythema as the most common after-effect of inflammatory acne and notes that it can last for years without treatment (IPL for post-acne erythema study). Usually, PIE is more noticeable in fair skin, although it can appear in any skin tone.

How to Tell PIH and PIE Apart

The simplest clue is colour. Brown or grey marks are usually PIH, whereas pink or red marks are usually PIE. However, many people have both at the same time, and the colours can overlap.

The Glass Press Test

In practice, a simple check is to press a clear glass or a clear plastic ruler gently onto the mark. If the mark fades or disappears under pressure, it is likely PIE, because pressing pushes blood out of the small vessels. In contrast, if the mark stays the same colour, it is likely PIH, since pigment does not move under pressure. Even so, this test is only a guide, and a doctor can confirm the diagnosis in person.

Are PIH and PIE Acne Scars?

Strictly speaking, neither is a true scar. In fact, both are flat colour changes, and the skin texture is normal. Therefore, they can fade with time and the right treatment. True acne scars, on the other hand, change the skin’s texture, such as indented rolling, boxcar or icepick scars. Those need different treatments, which are explained on our acne scar treatment page. For a Malay-language guide, read cara hilangkan parut jerawat (Bahasa Malaysia).

Step One for Both: Control the Acne

After all, every new breakout can leave a new mark. For this reason, controlling active acne is the first and most important step for both PIH and PIE. Our acne treatment page explains the options. In some cases of severe or stubborn acne, a doctor may consider isotretinoin, which requires careful medical supervision. Meanwhile, avoid picking or squeezing pimples, as this deepens both pigment and redness.

How to Treat PIH (Brown Marks)

Daily Sun Protection

Sun exposure darkens PIH and slows fading. Consequently, daily broad-spectrum sunscreen is essential. The American Academy of Dermatology recommends a tinted sunscreen with iron oxide for people with darker skin tones, because it also helps block visible light (AAD: how to fade dark spots in darker skin tones). For product guidance, see our guide to tinted sunscreen.

Skincare Ingredients

In addition, several ingredients help fade PIH gradually. For example, azelaic acid, vitamin C, niacinamide and retinoids are commonly used. Prescription options include tretinoin and, for stubborn marks, hydroquinone used under a doctor’s supervision. Importantly, harsh or irritating products can trigger more PIH, so it is wise to introduce one active at a time.

Chemical Peels

Superficial chemical peels can speed up the fading of surface pigment. However, the peel strength must suit your skin tone, as a strong peel can cause further darkening in Asian skin.

Pico Laser

For PIH that does not respond well to skincare, a pigment laser such as pico laser can help break up the excess melanin. However, in Asian skin, the doctor uses conservative settings to reduce the risk of rebound darkening.

How to Treat PIE (Red Marks)

Vascular Light or Laser Treatment

Because PIE comes from blood vessels, pigment lasers and lightening creams do little for it. Instead, treatments that target blood vessels are used, such as vascular lasers and intense pulsed light (IPL) with vascular filters. In the 2023 study above, IPL with a narrow-spectrum vascular filter improved post-acne redness more than a broad-spectrum filter or no treatment. Still, the study was small, so results in practice vary. At CLEO Clinic, a doctor will assess whether IPL treatment suits your skin.

Gentle Skincare

Irritation keeps the skin red, so a gentle routine helps PIE settle. This means a mild cleanser, a simple moisturiser and daily sunscreen, while avoiding harsh scrubs and over-exfoliating. Also, if redness spreads across the cheeks with flushing, it may be rosacea rather than PIE, which our guide to rosacea symptoms and triggers explains.

How Long Do PIH and PIE Take to Fade?

Both usually fade over time, although the timeline varies. According to the AAD, spots only a few shades darker than your skin often fade within 6 to 12 months, while deeper discolouration can take much longer. Similarly, PIE can last for months or even years without treatment. Still, treatment can shorten this timeline, provided new breakouts are kept under control. If you have also developed textured scars, read why acne scars take longer to fade.

When to Start Treatment

Usually, it is wiser to settle active acne before starting procedures such as lasers or peels. Our guide on when to start treatment after active breakouts explains the timing. Nevertheless, sunscreen and gentle skincare can start straight away.

Frequently Asked Questions

Can PIH and PIE happen at the same time?

Yes. Many people have both brown and red marks, sometimes in the same area. In that case, a doctor may combine treatments, for example sun protection and pigment care for PIH with vascular treatment for PIE.

Will whitening creams fade red marks?

No. Whitening and brightening creams target melanin, so they do not treat redness from blood vessels. Moreover, irritating creams can make PIE worse.

Are PIH and PIE permanent?

Usually not. Both are flat colour changes that tend to fade with time, especially with sun protection and acne control. However, some marks can persist for a long time without treatment.

Can I use pico laser for red marks?

Usually not. Pico laser targets pigment, so it is used mainly for brown marks. For red marks, a vascular treatment is usually more suitable.

Get Your Marks Assessed

Brown and red marks need different treatments, so getting the diagnosis right saves time and money. For an overview of all our pigment treatments, see pigmentation treatment in Kuala Lumpur. To have your marks checked by a doctor, book a consultation with CLEO Clinic.