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Published on: 1/30/2026
Cellulitis is a bacterial skin infection that typically shows up as a warm, red, swollen, and painful patch with ill-defined edges on one side of the body; if it worsens, you may see red streaks, blisters, or skin darkening. Spreading redness, increasing pain, fever or chills, numbness, or involvement of the face or genital area need urgent medical care and antibiotics, and conditions like diabetes or poor circulation can change the right next steps. There are several factors to consider. See below for complete details that can guide what you do next.
Cellulitis is a common but potentially serious skin infection. It happens when bacteria enter the skin through a crack, cut, insect bite, or other break. While many cases are mild and treatable, cellulitis can worsen if ignored. Understanding what cellulitis looks like, how it feels, and when it spreads can help you know when to act and when to seek medical care.
This guide uses information consistent with well‑established medical sources and clinical practice, explained in clear, everyday language.
Cellulitis is an infection of the deeper layers of the skin and the soft tissue beneath it. It is most often caused by common bacteria, such as Streptococcus or Staphylococcus, that normally live on the skin but cause problems when they get inside the body.
Cellulitis can happen anywhere, but it most commonly affects:
People of all ages can get cellulitis, though certain conditions increase risk (covered below).
One of the first signs of cellulitis is a patch of skin that looks different from the surrounding area. The appearance often changes over time.
Common visual symptoms include:
As cellulitis progresses, you may notice:
Cellulitis usually affects one side of the body, not both.
Cellulitis doesn’t just change how the skin looks—it also causes noticeable sensations.
People commonly describe cellulitis as:
In some cases, general symptoms can occur, such as:
These whole-body symptoms suggest the immune system is actively fighting the infection and should not be ignored.
In the early stages, cellulitis may look like a small red area that:
Prompt treatment at this stage often leads to a full recovery.
If cellulitis is not treated or does not respond to treatment, symptoms may escalate:
This is when cellulitis can become dangerous and needs urgent medical care.
Cellulitis spreads when bacteria move through the skin and into nearby tissues or the bloodstream.
It may spread:
Factors that increase the risk of spread include:
Spread does not mean panic—but it does mean medical attention is urgent.
Cellulitis can occur in the groin or genital region, where moisture and skin friction make infections more likely. In these areas, it may be harder to tell cellulitis apart from other rashes or skin conditions.
Signs of genital cellulitis may include:
Because genital symptoms can have many causes, you might consider doing a free, online symptom check for Genital Rashes to better understand what may be going on before speaking with a healthcare professional.
Anyone can develop cellulitis, but risk is higher if you:
Preventing skin injuries and treating small wounds promptly can reduce risk.
Doctors usually diagnose cellulitis based on:
Tests are not always needed, but in certain cases a doctor may order:
Most cases of cellulitis are treated with antibiotics, either by mouth or through an IV, depending on severity.
Treatment typically includes:
It’s important to:
You should speak to a doctor as soon as possible if you notice signs of cellulitis, especially if any of the following apply:
Early treatment can prevent complications and shorten recovery time.
If you’re unsure whether your symptoms are cellulitis or something else—especially in sensitive areas—getting reliable guidance early can make a meaningful difference.
(References)
* Mistry, R. D., & Thaler, D. E. (2023). Cellulitis and Erysipelas. *New England Journal of Medicine*, *388*(12), 1114–1122. doi:10.1056/NEJMcp2207436
* Raff, A. B., & Kroshinsky, D. (2015). Differentiating cellulitis from its mimics. *New England Journal of Medicine*, *372*(12), 1144–1152. doi:10.1056/NEJMra1402211
* Pasternack, M. S., & Swartz, M. N. (2019). Clinical progression of cellulitis treated with antibiotics: a systematic review and meta-analysis. *Clinical Infectious Diseases*, *68*(1), 15–23. doi:10.1093/cid/ciy519
* Jeng, A., Chen, S., & Hsueh, P. (2018). The clinical characteristics of bacterial cellulitis in adult patients. *American Journal of Emergency Medicine*, *36*(1), 15–18. doi:10.1016/j.ajem.2017.07.016
* Tan, C. S., Teo, Y. S., Lau, K. K., & Ho, K. K. (2024). The diagnosis and management of cellulitis: A systematic review. *Journal of the European Academy of Dermatology and Venereology*. Advance online publication. doi:10.1111/jdv.19902
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