Rheumatic fever and scarlet fever both occur due to a bacterial infection. However, they have some important differences to consider.

Rheumatic fever is a complication of under-managed bacterial infections. It can cause potentially deadly complications.

Scarlet fever can also occur due to a bacterial infection. It causes a rash and is generally mild. Left untreated, the underlying infection can cause rheumatic fever.

This article reviews what each condition is, their similarities and differences, treatment options, and more.

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Rheumatic fever is an immune-mediated disease that occurs primarily as a complication of group A streptococcal infections. In particular, untreated or poorly managed scarlet fever, strep throat, or strep skin infections can lead to its development.

The condition affects about 470,000 people annually.

Rheumatic fever can cause joint, heart, skin, or brain inflammation. If left untreated, it can lead to potentially fatal complications.

Anyone can develop rheumatic fever, but children between the ages of 5 and 15 and those in group settings, such as day care, have an increased risk. Also, those with limited access to healthcare may have an increased risk of developing the condition.

Common symptoms can include:

Scarlet fever is a red or discolored rash due to an infection from group A Streptococcus. This is the bacteria that causes strep throat.

Scarlet fever is often mild. It can cause symptoms that include:

  • sore throat and pain when swallowing
  • a fever (101°F or higher) or chills
  • stomach pain
  • nausea
  • headaches
  • body aches
  • vomiting

A person may also notice changes in the appearance of different body parts, including their tongue, neck, throat, and skin.

A rash typically appears within 2 days of the other symptoms’ onset, but it can take up to a week to appear or may even appear before other symptoms start. The rash often starts in the neck, underarms, and groin and then spreads across the body.

Physical characteristics of the rash include:

  • feels like sandpaper
  • peeling skin as the rash fades
  • a pale area around the mouth
  • brighter red or discoloration more in skin creases

The condition is more common in children than adults. Strep throat is the underlying cause in 15–30% of children between 5 and 15 years old. Infected skin, such as from burns, can also lead to scarlet fever.

Left untreated or under-managed, it can lead to several complications, including rheumatic fever.

Scarlet fever is relatively mild. Rheumatic fever can cause long-term damage to the heart, affect other areas of the body, and increase the risk of potentially serious complications, including death.

Scarlet fever can lead to rheumatic fever, but rheumatic fever does not cause scarlet fever.

Another difference is that scarlet fever is easily passed on to other people, but rheumatic fever is not contagious.

Both scarlet and rheumatic fever occur due to an infection from group A Streptococcus.

Both are also more common in children than adults, though they can affect either population. Neither is common in children under the age of 3.

Both rheumatic fever and scarlet fever require antibiotics to treat the underlying condition. Healthcare professionals may also prescribe or recommend treatments to help manage symptoms.

Rheumatic fever

Rheumatic fever treatment often involves three parts, including:

  • destroying the bacteria with antibiotics, commonly penicillin
  • treating symptoms, using medications for arthritis, anti-inflammatory medications, heart medications, or surgery
  • regular treatment with antibiotics to prevent recurrence

Some people develop long-term heart damage, known as rheumatic heart disease. These people may require additional treatment to address the condition. This may include surgical procedures or medications.

Scarlet fever

Doctors treat scarlet fever with antibiotics.

A person should complete any antibiotic regimen as prescribed.

General guidelines suggest a person can return to work, day care, or school when they no longer have a fever and have taken antibiotics for at least 12 to 24 hours.

The following sections provide answers to frequently asked questions about rheumatic and scarlet fever.

What is scarlet fever called now?

Scarlet fever is also called scarlatina. The name comes from the scarlatiniform rash associated with strep throat.

What disease is mistaken for scarlet fever?

At times, scarlet fever may present atypically, or healthcare professionals may mistake symptoms for another underlying cause. Illnesses that people may mistake for scarlet fever include viral infections, Kawasaki disease, or toxic shock.

How can you tell the difference between strep and scarlet fever?

Strep throat and scarlet fever occur due to the same bacteria. Both are associated with a painful sore throat and fever, but scarlet fever will present with a rash that often covers the body.

Scarlet fever can cause rheumatic fever if left untreated. Both occur due to the same bacteria that causes strep throat.

Rheumatic fever is generally more serious and affects several organs in the body, including the heart. Left untreated, it can lead to permanent heart damage and may be fatal.

Treatments for each involve antibiotics. People with rheumatic fever often require both prophylactic antibiotic treatment to prevent recurrence and treatment for any complications that may occur.