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Red, hot, swollen joint

Also called: Acute arthritis, hot joint, septic arthritis, gout flare

A red, hot, swollen joint that comes on suddenly is often gout, but it can also be a joint infection (septic arthritis), which can destroy the joint within days. Any hot, swollen joint with fever, or a swollen joint after a cut or injection, needs care the same day.

Common causesGout, pseudogout, joint infection, injury
Usually serious?Can be
Get checked ifAlways the same day, especially with fever
If you think it's an emergency, call 911.Thinking about suicide? Call or text 988.

Overview

Gout causes sudden, intense pain, redness, and swelling, often in the big toe, ankle, or knee, frequently starting at night. Pseudogout is similar and often affects the knee or wrist in older adults.

Septic arthritis is a bacterial infection inside a joint. It usually affects one joint, often the knee, with fever and severe pain moving the joint. It's more likely with diabetes, joint replacements, injected drug use, and recent joint injections.

When to get medical care

Call 911A hot, swollen joint with high fever, confusion, or feeling very sick.
Get care todayAny red, hot, swollen joint, especially with fever or chills. A swollen joint after a cut, bite, or injection. A painful, swollen artificial joint. Can't move the joint.
See a doctor soonJoint flares that keep coming back. Several joints swelling at once.

Causes

Causes include gout, pseudogout, septic arthritis, injury and bleeding into the joint, reactive arthritis after infections, Lyme disease, rheumatoid arthritis, and psoriatic arthritis.

OwieClear has pages on 3 conditions that can cause red, hot, swollen joint. Each shows how soon to get care.

Common causes

  • GoutOften needs care today

    A type of arthritis caused by uric acid crystals in a joint.

  • Joint infection (septic arthritis)Often needs care today

    A bacterial infection inside a joint.

  • Pseudogout (CPPD)Often needs care today

    Calcium crystals in a joint cause sudden attacks of pain, swelling, warmth, and redness, most often in the knee or wrist, like gout.

What you can do at home

  • Rest and raise the joint.
  • Ice for 15 to 20 minutes at a time.
  • Drink water.
  • Avoid alcohol during a gout flare.

Medicines

Gout is treated with NSAIDs, colchicine, or steroids. Joint infections need drainage and IV antibiotics. Don't take leftover steroids for a hot joint until infection is ruled out.

At the doctor

Fluid from the joint shows whether it's infection or crystals.

Questions you may be asked

  • When it started
  • Fever
  • Past gout
  • Injury, cuts, or injections
  • Diabetes or artificial joints

The exam

A joint exam.

Tests

  • Joint fluid test for crystals and infection
  • Blood tests
  • X-rays

Prevention

You can lower your risk.

  • Limit alcohol and sugary drinks if you have gout
  • Take uric acid medicine as prescribed
  • Treat skin wounds

Check your symptoms

Most symptoms have more than one possible cause. The symptom checker looks at all of your symptoms together, plus your age, and shows how soon to get care.

Start the symptom checker

Sources

Last updated 2026-11-13.