A staph infection typically starts as a small red bump on the skin that resembles a pimple or insect bite. As it develops, the area becomes swollen, warm to the touch, painful, and often fills with white or yellow pus. The exact appearance depends on the type of staph infection, but skin discoloration (red, purple, or brown depending on your skin tone), warmth, and drainage are the hallmarks.
The Early Stages
Most staph skin infections begin as a bump that looks unremarkable. It might resemble a small pimple, an ingrown hair, or even a spider bite. Within days, though, the bump grows harder, more painful, and more swollen. The skin around it changes color and feels noticeably warm compared to the surrounding area.
If the infection progresses, that small bump can turn into a firm, painful lump filled with pus. The pus is typically white or yellowish, and when the lump eventually opens or is drained, the fluid may ooze or leak. A fever can develop alongside the skin changes, which signals the infection is becoming more serious.
Common Types and How They Look
Folliculitis
This is the mildest form. It looks like small pus-filled bumps clustered around hair follicles, almost identical to acne. You can often see a hair shaft poking through the center of each bump. These are usually tender but not deeply painful, and they heal without scarring. When the infection pushes deeper into the follicle, the surrounding skin becomes more swollen and red.
Boils and Carbuncles
A boil (also called a furuncle) is a deeper pocket of pus that forms around a hair follicle. It starts as a red, tender lump and gradually fills until it develops a visible white or yellow tip. Boils are painful and firm to the touch. A carbuncle is a cluster of boils connected beneath the skin’s surface, creating a larger, deeper area of infection that tends to cause more scarring.
Impetigo
Impetigo is especially common in children and has a distinctive look. The most typical form starts as small sores or clusters of tiny blisters that break open and leave behind a honey-yellow crust on the skin’s surface. It usually shows up on the face, arms, and legs. There’s also a less common form that produces larger, fluid-filled blisters (roughly 2 to 5 centimeters across) containing clear or yellowish fluid. These blisters are thin-walled, rupture easily, and leave behind raw, exposed patches of skin.
Cellulitis
Cellulitis looks different from the other types because it doesn’t form a distinct bump or blister. Instead, you’ll see a spreading area of redness, swelling, and warmth on the skin. The borders of the redness are poorly defined, almost like the color is bleeding outward. The skin feels tight and painful, and the affected area can expand over hours. Cellulitis affects deeper layers of skin, so there’s no visible pus on the surface.
Staph on Different Skin Tones
The “redness” that most descriptions mention doesn’t look the same on everyone. On lighter skin, a staph infection typically appears bright red. On darker skin tones, the discoloration may show up as a deeper shade of brown, purple, or dark red that can be harder to spot visually. Warmth, swelling, pain, and hardness of the skin are more reliable indicators than color alone.
How It Differs From a Spider Bite
Staph infections are frequently mistaken for spider bites, and the confusion goes both ways. Both start as red, swollen, painful spots. The key differences: staph infections are more likely to be filled with white or yellow pus and feel warm to the touch. They also tend to worsen steadily over days rather than improving. A true spider bite typically heals on its own within a couple of days, while a staph abscess keeps growing. If you’re unsure, the presence of pus and increasing warmth points more toward staph.
Signs the Infection Is Spreading
One visual warning sign that a staph infection is getting worse is the appearance of red streaks extending outward from the infected area along the skin. These streaks follow the path of lymph vessels and indicate the infection is moving into the lymphatic system. The streaks are typically thin, clearly defined red lines radiating away from the original site.
Other signs of a worsening infection include the area of redness expanding rapidly, increasing pain or firmness in the surrounding skin, and the development of fever. Any of these changes mean the infection needs prompt medical attention.
MRSA vs. Regular Staph
There’s no way to tell whether a staph infection is MRSA (methicillin-resistant) just by looking at it. MRSA and regular staph infections look identical on the skin. Both can appear as red, swollen, painful bumps that may be full of pus. The only difference is how the bacteria respond to antibiotics, which requires lab testing to determine. MRSA infections do have a reputation for progressing quickly from small red bumps to deep, painful abscesses, but regular staph can do the same.
Staph in Infants and Young Children
In rare cases, staph bacteria can cause a condition in infants and young children where the skin looks as if it’s been scalded or burned. This produces a widespread, painful rash with thin, deflated-looking blisters that hang downward on the skin. The skin peels or flakes off with light pressure, leaving behind raw, moist patches. This is a medical emergency and looks dramatically different from a typical localized staph bump. It tends to spread across large areas of the body rather than staying confined to one spot.