Red and Brown Spots After Acne: What is the Difference Between PIE and PIH?

Why do acne scars remain?

After acne heals, two different types of scarring or discoloration may remain on the skin: red/pink spots and brown/dark spots.

These are not true acne scars. The red spots are often referred to as post-inflammatory erythema (PIE), while the brown spots are called post-inflammatory hyperpigmentation (PIH).

This distinction is important because the biology and treatment of PIE and PIH are not the same.

What is PIE?

PIE is a red, pink, or purplish discoloration of the skin that remains after inflammation. During acne inflammation, dilation of superficial dermal vessels and a local vascular response occur.

After active acne clears up, vascular redness may persist for some time. PIE is primarily a vascular problem, not a pigment issue.

What is PIH?

PIH refers to brown, gray-brown, or darker spots that appear as a result of increased melanin production following inflammation.

PihD (Pimples and Acne Disorders) may be more frequent and more persistent, especially in people with darker skin types, those with more intense acne, and those who squeeze or pick at their pimples.

How to distinguish between PIE and PIH?

PIE is red, pink, or purplish and is of vascular origin. PIH is light brown, dark brown, or gray-brown and is of melanin origin.

These two conditions can coexist, especially in darker skin types, and distinguishing them with the naked eye isn't always easy.

Is it the same thing as an acne scar?

No. Acne scarring involves a real change in the skin's structure: there may be depressions, tissue loss, swelling, or fibrosis.

In PIE and PIH, the skin surface may be normal; the problem is primarily color. PIE, PIH, and atrophic scarring can all be present in the same patient.

Why do some people get red spots while others get brown spots?

Skin phototype, severity of inflammation, genetic predisposition, sun exposure, skin-picking habits, and treatments used all play a role.

While PIE may be more visible in lighter skin tones, PIH may be more frequent and more persistent in darker skin types.

Does PIE resolve on its own?

Often it may lessen over time; however, in some patients it may persist for months or even longer. If new acne constantly appears, it becomes more difficult to reduce redness.

Does PID resolve on its own?

Yes, superficial epidermal PIH, in particular, can clear up over time. However, the process can take months, sometimes even longer. If the pigment has penetrated down to the dermis, clearing may be slower.

Is the most important treatment to stop new pimples from appearing?

Yes. One of the most important principles of PIH treatment is to stop new inflammation.

Treating only existing blemishes while new pimples keep appearing will only lead to the continuous formation of new blemishes.

Does squeezing pimples worsen blemishes?

Yes. Squeezing and picking can increase inflammation, deepen epidermal damage, increase the risk of PDI, and contribute to scarring.

Does sunlight darken PIH?

Yes. Ultraviolet and visible light can increase melanin production. Therefore, photoprotection is important in the treatment of PID.

Which creams can be used in PIH treatment?

Retinoids, azelaic acid, hydroquinone, some anti-pigmentation agents, and antioxidants can be used. However, aggressive treatments that cause irritation can paradoxically create new PIHs (Pilates of Hyperpigmentation).

Why might azelaic acid be important?

Azelaic acid is an agent that can be effective against both acne inflammation and pigmentation. Therefore, it may be significant in patients with both active acne and PIH (Pilarial Immunodeficiency Disease).

Do retinoids help with blemishes?

Retinoids can reduce comedone formation, treat active acne, regulate the epidermal cell turnover, and help disperse pigment.

However, proper use is important because excessive irritation can worsen PIH.

Are creams effective in treating PIE?

Because PIE is primarily vascular, pigment-reducing creams have limited effectiveness. Some anti-inflammatory or barrier-supporting products may help reduce redness; in persistent PIE, vascular-targeted therapies may be more effective.

Which lasers can be used in PIE?

Vascular laser and light systems can be considered. Pulsed Dye Laser (PDL), 532 nm vascular lasers, intense pulsed light (IPL), and some yellow light lasers are among the options.

What is PDL?

Pulsed Dye Laser (PDL) is a type of vascular laser that specifically targets hemoglobin. It typically operates at a wavelength of 585–595 nm.

The goal of PIE is to target superficial vessels, reduce diffuse redness, and control the vascular component.

Does IPL work in PIE?

It can be used in suitable patients. IPL may be advantageous if redness, diffuse vascular appearance, and some pigment irregularities are present simultaneously. Parameter selection is important in dark skin.

Can a Q-Switch laser be used in PIH?

It can be used in selected patients; however, caution should be exercised. Aggressive pigment lasers may cause new inflammation, rebound hyperpigmentation, or pigment irregularities.

Can BabyFace Ultra / thulium laser be used in PIH?

Yes. A 1927 nm non-ablative fractional thulium laser may be considered, particularly in selected patients with epidermal PIH, widespread pigment dysregulation, and concomitant photodamage.

If active inflammation persists, it's more important to control the acne first.

Is chemical peeling possible at PIH?

Yes. Glycolic acid, salicylic acid, and some combination superficial peels can help. However, very aggressive peels can create new PHIs (Pelvic Inflammatory Diseases).

What to do if PIE and PIH are present simultaneously?

This is very common. The patient may have red PIE, brown PIH, and several atrophic acne scars simultaneously.

In this case, medical treatment for active acne, vascular treatment for PIE, pigment-modifying treatment for PIH, and a layered approach such as subcision/microneedling/laser for scarring may be necessary.

Should blemishes or acne be treated first?

Generally, active acne should be brought under control first. However, appropriate topical treatments can target both acne and pigmentation simultaneously.

Will PIE or PIH completely disappear?

In most patients, it can be significantly reduced. Skin type, depth of pigmentation, duration of inflammation, sun exposure, and the persistence of active acne all affect the speed of the result.

Why do red spots turn brown after acne?

In some patients, while vascular redness is initially predominant, melanin production may increase over time, and PIH may develop in the same area. Sun exposure, ongoing inflammation, and tampering can facilitate this transformation.

Frequently Asked Questions

What are red spots after acne? They are mostly PIE (Pelvic Inflammatory Epidermolysis Bullosa) and are of vascular origin.

What are brown spots after acne? They are mostly PIH (Pelvic Inflammatory Disease) and are due to increased melanin production.

Are PIE and PIH the same thing? No. PIE is a vascular problem, PIH is a pigmentary problem.

Can red spots be treated with laser? For persistent PIE, PDL, IPL, or other vascular lasers can be used.

Can BabyFace Ultra be used for brown spots? A 1927 nm thulium laser may be considered in selected cases of epidermal PIH.

Does Q-Switch work for red spots? Since PIE's primary target is blood vessels, not pigment, Q-Switch is not the first choice.

Are acne marks scars? No. Discoloration is not a scar; however, it can occur in the same person.

Dermatologist's Note

The term "scar" after acne actually confuses three different problems: PIE — red blood cell-related scarring; PIH — brown pigmentation scarring; and true acne scarring — a permanent change in skin texture.

To ensure successful treatment, it's first necessary to identify which one is dominant.

Applying a pigment laser to a red PIE or attempting to treat a brown PIE solely with a vascular laser is not the correct approach.

Especially if active acne persists, the primary goal is to stop new inflammation. Then, depending on the patient's needs, topical treatments, peels, Q-Switch, BabyFace Ultra / 1927 nm thulium, or vascular lasers can be used in various combinations.

The basic principle: There is no single treatment for "acne scars"; the first step is to correctly identify the type of scar.