How is Post-Inflammatory Hyperpigmentation (PIH) different from atrophic acne scars? How to identify and treat each type

This article has been compiled and clinically reviewed by the Dermatology Specialists at BonBoz Clinic.

Post-acne dark spots are flat, discolored marks caused by post-inflammatory hyperpigmentation (PIH) that tend to fade over time. In contrast, atrophic (pitted) scars are depressions in the skin caused by collagen destruction, which rarely heal on their own. Because their underlying nature is entirely different, their treatment approaches also differ — correctly identifying the type of lesion is crucial to avoid ineffective treatments.

What is Post-Inflammatory Hyperpigmentation (PIH)?

After an inflammatory acne lesion heals, it can leave behind a brown, gray, or pinkish-red mark. This is a post-inflammatory hyperpigmentation response — the skin surface remains flat, only the color changes. These dark spots typically fade over several weeks to months, but sun exposure and picking at the skin can make them darker and more persistent.

How Do Pitted Scars Differ from Dark Spots?

Pitted scars are sunken areas of the skin caused by deep damage to the dermis. Unlike dark spots, pitted scars do not fill in on their own because the deficit lies in the collagen structure, not the pigment. You can feel the uneven texture by touching the skin or observing it under angled lighting.

How to Quickly Tell Them Apart at Home

A simple trick: shine a light at an angle across your skin. If the mark is only discolored but the surface remains flat, it is highly likely to be a dark spot. If a shadow appears due to a depressed surface, that is a sign of a pitted scar. However, many people experience both simultaneously, making a professional assessment by a doctor the most accurate method.

Treatment Approach for Dark Spots

Since this is a pigmentation issue, post-acne dark spots are typically addressed through skincare that evens out skin tone and provides sun protection, combined with active acne management to prevent new marks from forming. A doctor will recommend the most suitable solution for your specific skin condition.

Treatment Approach for Pitted Scars

Pitted scars require interventions that target the underlying collagen structure; waiting rarely helps them fill back in. The treatment plan depends on the scar type (base shape), depth, and whether active acne is still present, requiring a doctor's skin analysis and a personalized approach.

Why Should Acne Be Controlled Before Treating Scars?

If inflammatory acne is still active, new lesions will continuously generate new dark spots and scars, making it difficult to achieve optimal treatment results. Controlling acne first ensures a stable skin foundation and leads to more sustainable scar treatment outcomes.

Frequently Asked Questions

Do post-acne dark spots go away on their own?

Most fade over time if you protect your skin from the sun and avoid picking at it; however, the recovery rate varies from person to person.

Can I treat dark spots and pitted scars at the same time?

It depends on your skin condition; a doctor will prioritize the treatment steps accordingly after a clinical examination.

Why are my dark spots not fading?

This is often due to sun exposure, improper skincare, or recurring acne; a professional evaluation is needed to identify the exact cause.

If you are unsure whether you have dark spots or pitted scars, schedule an appointment for a professional skin analysis and personalized consultation with our doctors.