Skin Infection
Skin infection is a broad description, not a single diagnosis. Bacteria, fungi, viruses and parasites can affect different layers of skin and require different treatment.
Key points
- Crusting, blisters, pus, spreading warmth, ring-shaped scale and grouped painful vesicles point toward different causes.
- Depth, speed of spread, wound or bite exposure, immune status and systemic symptoms determine urgency and testing.
- Antibiotics do not treat fungal or viral disease, and an abscess may need drainage rather than a different tablet.
Catalogue matches do not identify the cause or indicate that an antibiotic or other antimicrobial is suitable.
What information helps distinguish infections?
Clinicians consider whether the rash is painful or itchy, superficial or deep, localised or spreading. Culture, scraping or viral testing may help in selected cases. Non-infectious inflammation can also mimic infection.
How is bacterial treatment selected?
When bacterial infection is likely, site, severity, pus, allergy and resistance guide treatment. Azithromycin and roxithromycin are not automatic choices for common skin infection. Source control and wound care may matter more; see antibiotics.
When to seek urgent care
Seek urgent care for rapid spread, severe pain, fever, red streaking, eye or facial involvement, dark or numb skin, confusion, or infection in a severely immunocompromised person.

