Acne marks: why are the red ones and brown ones different?

If a mark stays after acne clears, you care for it differently depending on its color. A red mark is dilated blood vessels showing through where inflammation passed (postinflammatory erythema, PIE) (Bae-Harboe & Graber, 2013), while a brown mark is pigment left when inflammation drove extra melanin (postinflammatory hyperpigmentation, PIH) (Davis & Callender, 2010). Unlike a true scar — pitted or raised tissue change — both fade over time, but squeezing or irritating them makes them last longer. So don't irritate them; block UV and calm the skin.

Just as acne finally settles, a red or brownish mark stays in its place, and you're anxious again about when it will go.

Post-acne marks are common, though how common depends a lot on skin tone: comparing women by ethnicity, hyperpigmentation was seen in 65% of African American and 48% of Hispanic women, against 10–25% of Asian, Continental Indian, and Caucasian women (Perkins et al., 2011). The researchers noted that acne's after-effects were more common in darker skin types.

Red marks vs brown marks: what's the difference?

Even acne marks differ in what they are. A red mark briefly blanches when pressed and then reddens again; a brown mark keeps its color when pressed. A red mark is dilated vessels showing through where inflammation passed (Bae-Harboe & Graber, 2013); a brown mark is pigment from inflammation overdriving melanin (Davis & Callender, 2010). Both are flat 'marks' that fade over time. A pitted or raised change, by contrast, is a true scar — changed tissue that won't vanish on its own. For telling a mark from a scar, see acne scars, why they won't fade; for the same pigment-versus-vascular split, see dark circles, pigment vs vascular.

Why do acne marks linger?

Both are rooted in inflammation. The longer or more often inflammation recurs, the darker and longer marks are thought to stay. Squeezing or scrubbing enlarges the inflammation, which can set red marks redder and brown marks deeper. And UV re-provokes the melanin of brown marks, making them last longer (Davis & Callender, 2010). In the end, the irritation you add to erase a mark fast is what holds it there.

How do you care for acne marks by their color?

First, don't squeeze. Squeezing acne or scrubbing a mark brings inflammation back. Next, settle the residual inflammation with gentle soothers like centella and panthenol, plus ceramide moisture. Block UV by day; UV makes brown marks last longer (Davis & Callender, 2010). If pigment bothers you, add just one brightener commonly used for brown marks, like niacinamide or azelaic acid, in a small amount. Piling on strong acids (vitamin C, glycolic, lactic, salicylic) or brighteners at once can stack irritation and stoke inflammation, so hold back. Care for red marks with calming and time, and brown marks with sun protection and a gentle brightener.

In short, ease the inflammation before rushing to erase marks

Acne marks aren't a sign of weak skin; they mean skin is clearing the trace inflammation left. Widened vessels showing through make a red mark, leftover melanin a brown one (Bae-Harboe & Graber, 2013; Davis & Callender, 2010), and UV makes brown marks last longer. Rather than piling on irritation to erase them fast, don't squeeze, calm the skin, and block UV. A pitted scar belongs to dermatological procedures. How long the redness lasts afterwards is set out in redness after a laser.

One step today

• Don't squeeze or scrub acne or marks; calm the inflammation first with gentle soothers like centella and panthenol plus ceramide moisture. Whether not squeezing reduces marks hasn't been tested in a trial. Press the mark with a finger: if it briefly blanches and reddens again, it's a red mark; if not, a brown mark (Bae-Harboe & Graber, 2013). If marks start to pit or acne keeps festering, see a dermatologist.
• If it's a brown mark, block UV by day. UV re-provokes the melanin in brown marks and makes them last longer (Davis & Callender, 2010). Take photos in the same light and compare whether the color is deepening. If color spreads beyond the mark or its shape keeps changing, see a dermatologist.
• If you want a brightener, add just one — niacinamide or azelaic acid — in a small amount. Both are commonly used for brown marks. Watch for stinging or redness over the first few days; stop if stinging continues, and see a dermatologist if the color hasn't changed after several months.