Scars on your back can come from a surprising number of sources, and many people discover them without remembering any specific injury. The back is one of the most common sites for scarring because the skin there is thick, under constant tension from movement, and prone to conditions like acne and folliculitis that can leave permanent marks. Understanding the likely cause depends on what your scars look like: whether they’re raised, depressed, flat and discolored, or stretched out horizontally.
Back Acne Is the Most Common Cause
If your scars are scattered across your upper back and shoulders, acne is the most likely explanation. Truncal acne (acne on the torso) affects a large portion of people who also get facial acne, and the back is especially vulnerable because it has a high concentration of oil glands. The problem is that many people don’t treat back acne as aggressively as they treat their face, so breakouts linger longer and penetrate deeper into the skin. That deeper inflammation is what destroys tissue and creates scars.
Back acne scars come in two main forms. Depressed scars look like small pits or shallow dips in the skin where tissue was lost during healing. Raised scars, including hypertrophic scars and keloids, happen when your body overproduces collagen during repair. The back and shoulders are particularly prone to raised scarring. About 15% of all scars from skin injuries eventually develop into hypertrophic scars or keloids, and having a biological relative who forms keloids significantly increases your risk.
Folliculitis and Skin Infections
Folliculitis is an infection of the hair follicles that causes clusters of small, pus-filled bumps. It’s extremely common on the back, where friction from clothing, sweat, and bacteria create ideal conditions. One type caused by yeast produces an itchy rash concentrated on the back and chest. Most mild cases clear on their own, but severe or repeated infections can destroy the follicle and surrounding tissue, leaving permanent scars. If you’ve had recurring episodes of painful, tender bumps on your back that eventually crusted over, folliculitis scarring is a strong possibility.
Boils and carbuncles (clusters of connected boils) are deeper infections that almost always leave a mark. These form hard, painful lumps under the skin that eventually drain, and the damage they cause during healing tends to produce noticeable depressed or discolored scars.
Chickenpox and Shingles Scars
Small, round, slightly sunken scars scattered across the back are a hallmark of chickenpox. Between 7% and 18% of people who’ve had chickenpox develop permanent depressed scars. The trunk is one of the areas most heavily affected by the rash, so it’s common to find these marks on your back even decades later. If you had chickenpox as a child, you may not remember it clearly, but the scars have a distinct look: small, round divots that are slightly paler or darker than the surrounding skin.
Shingles, caused by the same virus reactivating later in life, typically follows a band-like pattern on one side of the torso. Scarring from shingles tends to be more linear and localized to that band rather than scattered randomly.
Stretch Marks Mistaken for Scars
Horizontal lines across the lower back are frequently mistaken for scars, but they’re actually stretch marks caused by rapid growth. A study of teenage boys with these marks found that two-thirds had experienced a significant growth spurt before the lines appeared. Tall stature and a family history of stretch marks were also strong predictors. These marks form when skin stretches faster than the underlying connective tissue can keep up, causing small tears in the deeper layers.
Stretch marks start out pink, red, or purple, then gradually fade to white or silver. They feel slightly different in texture from the surrounding skin, often smoother or slightly indented. Rapid weight gain, pregnancy, or bodybuilding can produce similar marks higher up on the back, particularly around the shoulders.
Surgical and Injury Scars
Any break in the skin from a cut, burn, scrape, or surgical procedure will produce a scar in adults. Roughly 100 million people worldwide acquire scars from surgery or trauma each year. The back is under constant mechanical stress from bending and twisting, which means wounds in this area tend to heal with thicker, more noticeable scars. Surgical scars on the back are also harder to care for during healing because they’re difficult to see and protect.
Burn scars on the back, even from relatively minor sunburns that blistered severely, can leave lasting discoloration or textural changes. Scars from deeper burns are typically raised, tight, and may restrict movement if they’re large enough.
What Affects How Your Scars Formed
Several factors determine why some people scar more prominently than others. Genetics play a major role: your body’s tendency to overproduce or underproduce collagen during wound repair is largely inherited. Age matters too. Younger skin tends to produce more collagen, which is why teenagers and young adults are more prone to raised, thick scars. Skin tone is another factor, with darker skin tones carrying a higher risk of keloid formation and post-inflammatory hyperpigmentation (dark spots left after inflammation fades).
The location itself is significant. The back, chest, shoulders, and jawline are high-tension areas where skin is constantly being pulled and stretched. This mechanical force encourages the body to lay down extra collagen, which is why even minor injuries in these zones can produce disproportionately visible scars.
Treating Back Scars
Treatment depends on the type of scar. For raised scars and keloids, a dermatologist can inject the scar tissue with corticosteroids to flatten it, or use cryotherapy (freezing) to reduce its size. These approaches work best on newer scars but can still improve older ones over time.
For depressed scars from acne or chickenpox, laser treatments are the most studied option. Fractional lasers work by creating tiny controlled injuries in the scar tissue, prompting the skin to rebuild with smoother, more even collagen. Multiple sessions are typically needed, and results vary depending on scar depth and skin type. Pulsed dye lasers are effective for scars that are still red or discolored.
At-home options have more modest results but are worth trying for mild scarring. Silicone gel sheets, worn over scars for several hours daily, can slightly improve the appearance of raised scars. A Cochrane review found them slightly more effective than onion extract gels (a common drugstore option) for hypertrophic scars. For preventing new acne scars, treating breakouts early with products containing benzoyl peroxide, salicylic acid, or a retinoid like adapalene can reduce the inflammation that leads to permanent damage.
Identifying Your Scars
A few visual clues can help you narrow down the cause:
- Small, scattered round pits: likely chickenpox scars
- Raised, firm bumps on upper back and shoulders: likely keloids or hypertrophic scars from acne
- Shallow depressions mixed with dark spots: likely acne scarring with post-inflammatory pigmentation
- Horizontal pale or silvery lines on the lower back: stretch marks from a growth spurt
- A band of scars on one side: likely shingles
- Clusters of small pitted marks near hair follicles: likely folliculitis scarring
If your scars are growing, changing color, or appearing without any clear cause, a dermatologist can examine the tissue and rule out less common conditions. For most people, back scars are a cosmetic concern with a straightforward explanation, even if the original cause happened years ago.