Staph infections on the skin most often look like a red, swollen bump filled with pus, similar to a large pimple or boil. But staph bacteria cause several distinct types of skin infections, and each one has a different appearance. Knowing what to look for helps you tell a harmless blemish from something that needs treatment.
The Most Common Look: Boils and Abscesses
The classic staph skin infection starts as a small bump that resembles a pimple or acne breakout, then quickly becomes a hard, painful red lump filled with pus or a cluster of pus-filled blisters. These are called boils (or furuncles when they form around a hair follicle). They tend to appear in areas prone to friction or sweating: the armpits, groin, buttocks, and inner thighs.
As a boil matures, the center softens and develops a visible white or yellow point where pus has collected near the surface. The surrounding skin turns red, feels warm, and is tender to the touch. A fully developed abscess feels slightly squishy when pressed, unlike a firm cyst or tumor. When the overlying skin becomes very thin and almost translucent, the abscess is close to draining on its own.
Most boils range from the size of a pea to the size of a golf ball. If several boils cluster together and connect beneath the skin, they form a carbuncle, which is larger, deeper, and often accompanied by fever or general fatigue.
Impetigo: Honey-Colored Crusting
Impetigo is a highly contagious staph infection that primarily affects young children, though adults can get it too. It looks different from a boil. The infection begins as reddish sores, most often around the nose and mouth. These sores rupture quickly, ooze for a few days, and then form a distinctive honey-colored crust that sits on top of the skin. This golden, flaky crusting is the hallmark sign.
A less common form called bullous impetigo produces larger, fluid-filled blisters rather than crusted sores. These blisters typically appear on the trunk, arms, and legs, and are most common in infants and children under 2. The blisters are fragile, break easily, and leave behind raw, moist patches of skin.
Cellulitis: Spreading Redness Without a Head
Unlike a boil, which forms a distinct bump, cellulitis is a deeper skin infection that spreads outward. It looks like an expanding area of red, swollen skin that feels warm and painful. The redness doesn’t have a sharp border. Instead, it fades gradually into normal skin at the edges. There’s no central pus pocket visible on the surface.
Other visual clues include skin dimpling (a texture resembling an orange peel), small blisters scattered across the red area, and spots within the inflamed zone. The affected skin may look tight or shiny from swelling. Cellulitis most commonly develops on the lower legs, but it can appear anywhere. Fever and chills often accompany the skin changes, which is a sign the infection is affecting more than just the surface.
How Staph Differs From Acne
Staph folliculitis, an infection of the hair follicles, is one of the most commonly confused conditions with regular acne. The key differences come down to location, uniformity, and sensation.
- Location: Folliculitis tends to show up where hair grows and where shaving or friction occurs: the scalp, neck, beard area, thighs, and buttocks. Acne targets oil-rich zones like the face, chest, and upper back.
- Appearance: Folliculitis creates small, uniform, evenly sized pustules, each one centered around a hair. Acne is more varied, producing a mix of blackheads, whiteheads, deep nodules, and cysts of different sizes and stages.
- Sensation: Folliculitis is persistently itchy. Acne tends to cause tenderness and swelling rather than itching, especially when deeper nodules become inflamed.
If you’re getting uniform, itchy bumps in areas where you shave or wear tight clothing, staph folliculitis is more likely than acne.
Why Staph Gets Mistaken for Spider Bites
MRSA infections, caused by antibiotic-resistant staph bacteria, are so frequently mistaken for spider bites that many go untreated until they become serious. At the earliest stage, MRSA looks nearly identical to a minor bite or abrasion: a small red bump that’s slightly swollen and tender. There’s no reliable way to tell the two apart just by looking in the first day or two.
The difference becomes clearer as the infection progresses. A staph abscess grows rapidly over a few days, becoming increasingly painful, warm, and swollen. It often begins draining pus on its own or develops a visible pus-filled center. A true spider bite, by contrast, typically has a central puncture mark and doesn’t produce the same amount of thick drainage. If a “bite” keeps getting worse after 48 hours, is warm to the touch, and has no clear puncture wound, staph is the more likely explanation.
Serious Staph Infections in Children
Staphylococcal scalded skin syndrome is a rare but dramatic-looking infection that primarily affects newborns and young children. The staph bacteria release toxins that attack the top layer of skin, causing it to blister and peel off in large sheets. It starts with fussiness, fatigue, and fever, followed by widespread redness. Fluid-filled blisters form and break easily, leaving behind raw, moist skin that looks and feels like a burn. The peeling can be extensive, covering large areas of the body.
This condition looks alarming, and it requires immediate medical attention. The skin damage is caused by bacterial toxins circulating in the blood, not by the infection spreading across the skin surface, which is why the peeling can appear far from the original infection site.
Signs a Staph Infection Is Getting Worse
Most small staph skin infections stay localized and resolve with proper care. But certain visual changes signal that things are heading in a dangerous direction. Watch for redness that spreads beyond the original bump and keeps expanding over hours rather than days. Red streaks radiating outward from the infection suggest it’s moving into the lymphatic system.
A sudden, widespread rash that looks like a sunburn, especially alongside high fever and feeling very unwell, can indicate toxic shock syndrome, a rare but life-threatening complication. This rash is flat rather than bumpy, covers large areas of the body, and the skin may peel days later as it heals.
If a boil or abscess doesn’t come to a head or begin improving within a few days, applying warm compresses can help draw the infection to the surface. Squeezing or attempting to pop a staph abscess before it’s ready can push bacteria deeper into surrounding tissue and make the infection worse.