A staph infection on the skin typically appears as a red, swollen bump or patch that’s painful and warm to the touch, often filled with pus or drainage. But staph bacteria cause several distinct types of skin infections, and each one looks different. Knowing what to look for can help you tell a staph infection apart from a pimple, a spider bite, or a minor rash.
Boils: The Most Recognizable Form
Boils are the staph infection most people picture. They start as a small, painful red bump, sometimes no bigger than a pea, then grow over several days as pus collects inside. A single boil can enlarge to more than two inches across. The surrounding skin turns reddish or purplish and swells noticeably.
As the boil matures, a yellow-white tip develops at the center. This is the point where the boil will eventually rupture and drain thick, yellowish pus. Before it drains, the entire area feels firm and intensely tender. When multiple boils cluster together and connect beneath the skin, the resulting mass is called a carbuncle, which tends to be deeper and more painful.
Cellulitis: Spreading Redness Without a Head
Not all staph infections form a distinct bump. Cellulitis is an infection of the deeper skin layers that creates a broad area of redness, swelling, and warmth rather than a single pus-filled lump. The skin feels tight and painful, and touching it often reveals noticeable heat compared to the surrounding area.
Cellulitis can also cause skin dimpling (a texture resembling orange peel), blisters, and scattered spots within the red zone. Unlike a boil, cellulitis doesn’t have a clear center or a drainable pocket of pus. The redness tends to expand outward over hours to days, and it’s commonly accompanied by fever and chills. It most often shows up on the lower legs but can develop anywhere bacteria enter through a cut, scrape, or crack in the skin.
Folliculitis: Pus-Filled Bumps Around Hair
Staph folliculitis looks like small red or white pimples clustered around hair follicles. The bumps are pus-filled and can appear anywhere you have body hair, though they’re especially common on the thighs, buttocks, and beard area. The key difference from ordinary acne: these bumps tend to be itchy rather than just sore, and they often progress into crusty sores instead of resolving on their own.
Impetigo: Honey-Colored Crusts
Impetigo is most common in young children and has a very distinctive look. It starts as small raised bumps that quickly become pustules, then break open and leave behind thick, adherent crusts that are golden or honey-colored. These crusty patches usually appear on the face, particularly around the nose and mouth, though they can spread to other areas. The sores are highly contagious, and new patches often pop up near the original ones as the bacteria spread through the fluid that seeps from each lesion.
MRSA: Looks Like Regular Staph
MRSA (methicillin-resistant staph) doesn’t have a unique visual signature. You cannot tell by looking at the skin whether an infection is MRSA or a regular staph strain. MRSA skin infections appear as the same red, swollen, painful bumps that are warm to the touch and full of pus. The difference is in how the bacteria respond to antibiotics, not in how the infection looks.
One important note from the CDC: people frequently mistake MRSA skin infections for spider bites. Unless you actually saw a spider bite you, a painful red bump that’s growing and filling with pus is more likely to be a staph infection than a bite. MRSA infections can progress quickly, starting as small red bumps and turning into deep, painful abscesses within days.
Scalded Skin Syndrome: Large-Scale Peeling
Staphylococcal scalded skin syndrome is a rare but dramatic presentation, mostly affecting newborns and young children. The staph bacteria release toxins that cause widespread skin damage far from the original infection site. Large areas of skin redden, then develop thin blisters that break easily. The top layer of skin peels off in large sheets with even gentle touching, leaving raw areas that look like burns. Before the peeling starts, the skin may feel extremely tender and take on a wrinkled, tissue-paper consistency.
How to Tell Staph From a Spider Bite
Both staph infections and spider bites start as red, swollen, painful spots on the skin. The distinguishing features: staph infections are more likely to contain white or yellow pus, feel warm to the touch, and come with a fever. Spider bites are more likely to develop a purple or blue discoloration near the center, and most heal on their own within a couple of days. A spot that’s growing, getting more painful, and producing pus points toward staph rather than a bite.
Signs the Infection Is Spreading
A localized staph infection that stays in one spot is concerning but manageable. The warning sign that it’s moving deeper is the appearance of red streaks radiating outward from the infected area along the skin. These streaks indicate that the infection has entered the lymphatic system, a condition called lymphangitis, and it moves fast. Within less than 24 hours, the infection can spread from the original wound to multiple areas of the lymphatic system and potentially enter the bloodstream.
Other signs of a worsening infection include increasing redness that expands beyond the original borders, fever, chills, and skin that becomes more swollen or painful rather than improving over two to three days. An area of redness that’s visibly larger than it was a few hours ago, especially with a fever, needs prompt medical attention.