Quick answer. Cellulitis is a bacterial infection of the skin and soft tissue, usually caused by Streptococcus or Staphylococcus bacteria entering through a break in the skin. It most often affects the lower leg, causing an area of skin that is red, hot, swollen, tender and spreading, sometimes with fever and feeling unwell. Athlete’s foot, cuts, insect bites, eczema, leg swelling and diabetes raise the risk. Cellulitis needs prompt antibiotics (oral or, if severe, intravenous) – it does not clear on its own. In Singapore, see a GP or polyclinic quickly. Go to A&E or call 995 if the redness spreads fast, you have high fever, or the pain feels far worse than the skin looks – these can signal a serious infection.
Cellulitis is a common bacterial infection of the deeper layers of the skin and the soft tissue underneath. It happens when bacteria, usually Streptococcus or Staphylococcus, get in through a break in the skin and spread, leaving the area red, hot, swollen and painful. It most often affects the lower leg but can occur anywhere on the body.
Cellulitis is treatable, but it needs antibiotics promptly – it will not clear by itself, and an untreated infection can spread quickly and become dangerous. This guide explains the symptoms, common causes in Singapore, how it is treated, the red flags that mean you should go straight to A&E, and how to lower your risk of it coming back.
At a glance
| Feature | What it looks/feels like | What to do |
|---|---|---|
| Typical signs | Skin that is red, warm, swollen and tender – often on one lower leg; the redness may spread outwards over hours | See a GP or polyclinic promptly for antibiotics |
| Common triggers | A cut, scratch, insect bite, athlete's foot, eczema, leg ulcer or swollen legs that let bacteria in | Keep the area clean; treat athlete's foot and broken skin early |
| Higher risk | Diabetes, chronic leg swelling (lymphoedema), poor circulation, weakened immunity, older age, obesity | Manage underlying conditions; inspect feet daily |
| Mild cases | Localised redness, no high fever, otherwise well | Oral antibiotics; mark the edge of the redness to track spread |
| Severe / urgent | Rapidly spreading redness, high fever or chills, severe pain out of proportion, blistering or skin turning dark/grey, feeling very unwell | Go to A&E now or call 995 – possible necrotising (flesh-eating) infection |
What cellulitis feels and looks like
Cellulitis usually starts in one area and gets worse over hours to a day or two. Typical features include:
- Redness that may spread outwards and can feel warm to the touch
- Swelling and a tight, shiny appearance of the skin
- Pain or tenderness in the affected area
- Fever, chills or feeling generally unwell in more significant infections
- Sometimes blisters, oozing, or swollen lymph glands nearby
It most often affects the lower leg, but can also affect the arms, face or other areas. Cellulitis nearly always affects one side of the body (one leg, not both) – redness and swelling in both legs at once is more often due to other causes.
What causes it and who is at higher risk
Cellulitis happens when bacteria enter through a break in the skin. That break can be tiny and easy to miss. Common entry points include:
- Cuts, grazes, insect or animal bites, and puncture wounds
- Athlete’s foot (tinea) and cracked skin between the toes – a very common doorway for leg cellulitis
- Eczema, leg ulcers, or recent surgical wounds
You are at higher risk if you have diabetes, chronic leg swelling (lymphoedema) or poor circulation, a weakened immune system, eczema, or are older or overweight. Having had cellulitis once also makes future episodes more likely.
How cellulitis is treated in Singapore
Cellulitis is treated with antibiotics, and treatment should start promptly. A GP, polyclinic doctor or dermatologist will usually prescribe a course of oral antibiotics for mild to moderate cellulitis. It is important to finish the full course even once the skin improves – this supports recovery and responsible antibiotic use.
Improvement usually begins within 1-3 days of starting antibiotics, although redness and swelling can take a week or two to settle fully. Raising the affected limb and simple pain relief such as paracetamol can help. More severe cellulitis – high fever, fast spread, or in people with diabetes or weakened immunity – may need intravenous (IV) antibiotics and admission to hospital. If your symptoms are not improving after a couple of days of antibiotics, or are getting worse, go back to a doctor.
Red flags – when to go to A&E or call 995
Most cellulitis is treated successfully with antibiotics, but certain warning signs can mean a serious, deeper infection such as necrotising fasciitis (a rare but life-threatening ‘flesh-eating’ infection that needs emergency surgery). Get emergency care – go to a hospital A&E or call 995 – if you notice:
- Redness that is spreading rapidly (you can almost watch it grow), or that has spread well beyond a mark you drew earlier
- Severe pain that feels out of proportion to how the skin looks
- High fever, chills, a racing heart, confusion or feeling very unwell
- Skin turning dark, purple, grey or blistered, or numbness over the area
- Cellulitis on the face or around the eye, which can be more serious
When in doubt, seek care urgently. It is always safer to be checked.
Preventing cellulitis and recurrences
You can lower your risk by protecting your skin and treating problems early:
- Care for your feet – keep skin clean and moisturised, and treat athlete’s foot promptly (cracked skin between the toes is a common entry point)
- Clean cuts and grazes with running water and keep them covered until healed
- Moisturise dry skin to prevent cracks; manage eczema
- Manage swelling – elevate the legs and follow advice for lymphoedema or chronic leg swelling
- Keep diabetes well controlled and check your feet daily for cuts, blisters or redness
If you get cellulitis repeatedly, see a doctor – underlying causes such as lymphoedema or persistent athlete’s foot can often be treated, and in some cases preventive measures are advised.
Related guides
- Best Dermatology Clinics in Singapore — our editorial shortlist
- dermatology clinics directory
- Boils & abscesses
- Cold sores
- Scabies
Sources
- Singapore General Hospital (SGH) – Cellulitis
- National University Hospital (NUH) – Skin Infections
- SingHealth (GPFirst) – Cellulitis
- Diagnosis and management of cellulitis (NIH/PMC review)
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- Fungal Nail Infection (Onychomycosis) in Singapore
- Fungal Skin Infections in Singapore
- Viral Warts Treatment in Singapore
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