ConditionInfections
Scarlet Fever
Scarlet fever is an infection caused by group A Streptococcus (strep) bacteria that produce a toxin causing a red, rough, sandpaper-like rash. It usually comes with strep throat: sore throat, fever, swollen glands and a "strawberry tongue". It is most common in children aged 5 to 15. A rapid strep test or throat culture confirms it, and a course of antibiotics, usually penicillin or amoxicillin, cures it and prevents complications such as rheumatic fever. Children can return to school after 12 to 24 hours of antibiotics.
Also called: Scarlatina, streptococcal fever with rash
At a glance
- Cause
- Group A Streptococcus bacteria producing an erythrogenic toxin.
- Who gets it
- Mostly children 5 to 15; less common in adults.
- Symptoms
- Sore throat, fever, sandpaper rash starting on the neck and chest, strawberry tongue, flushed cheeks.
- Diagnosis
- Rapid strep test or throat culture.
- Treatment
- Antibiotics, usually penicillin or amoxicillin for 10 days.
- Contagious
- Until 12 to 24 hours after starting antibiotics.
When to get help
Call 911 or go to the ER
- Difficulty breathing, drooling or being unable to swallow saliva
- A child who is very drowsy, confused or hard to wake
- A rapidly spreading red, painful skin area with fever and feeling very unwell, or low blood pressure (possible invasive strep or toxic shock)
See a doctor within a day or two
- Sore throat with fever and a rough red rash: see a doctor the same day for a strep test
- A one-sided, severe sore throat with a muffled voice or difficulty opening the mouth
- Signs of dehydration, such as very little urine
- Not improving after 48 hours of antibiotics
Book a routine appointment
- Swollen, painful joints, or a new heart murmur, weeks after a strep infection
- Dark, cola-colored urine, face swelling or high blood pressure 1 to 3 weeks after strep (possible kidney inflammation)
Usually safe to manage at home
- Recovering on antibiotics with fever settling and eating and drinking normally
What causes scarlet fever
Scarlet fever is caused by Streptococcus pyogenes (group A strep). Some strains produce toxins that cause the characteristic rash. The bacteria usually infect the throat (strep throat) and, less often, the skin, such as in impetigo or wounds.
It spreads through:
- droplets from coughs and sneezes
- sharing cups, utensils or toys
- touching sores on infected skin
The incubation period is usually 2 to 5 days. Outbreaks are most common in late winter and spring.
Symptoms
Early symptoms
- sore throat, often with red, swollen tonsils that may have white patches
- fever of 38.3 °C (101 °F) or higher
- headache, stomach pain, nausea and vomiting, especially in children
- swollen, tender lymph nodes in the neck
The rash
The rash appears 12 to 48 hours after symptoms begin:
- tiny red bumps that feel rough, like sandpaper
- starts on the neck, chest and armpits, then spreads to the trunk and limbs
- more intense in skin folds such as the armpits, elbows and groin, forming red lines (Pastia's lines)
- blanches when pressed
- may be harder to see on darker skin, but the texture can still be felt
- fades after about a week, often followed by peeling, especially of the fingertips and toes, for several weeks
Other signs
- strawberry tongue: white coating early, then a red, bumpy tongue
- flushed cheeks with a pale ring around the mouth
- red spots on the roof of the mouth
Scarlet fever vs other rashes
| Illness | Distinguishing features |
|---|---|
| Scarlet fever | Sandpaper rash, sore throat, strawberry tongue, positive strep test |
| Kawasaki disease | Fever 5 days or more, red eyes without discharge, cracked lips, swollen hands and feet; usually under 5 |
| Measles | Cough, runny nose, red eyes, rash starting on the face |
| Viral rash | Often with cold symptoms, no sandpaper texture, strep test negative |
| Toxic shock syndrome | Sunburn-like rash with low blood pressure and severe illness |
Diagnosis
- Rapid strep test: a throat swab with results in minutes
- Throat culture: used when a rapid test is negative in children and teens, because rapid tests can miss some cases
Treatment
- Antibiotics: penicillin or amoxicillin for 10 days is standard. For penicillin allergy, alternatives include cephalexin, azithromycin or clindamycin, depending on the type of allergy. Finish the whole course even when feeling better
- Pain and fever relief: acetaminophen (paracetamol) or ibuprofen at the label dose. Do not give aspirin to children or teenagers
- Fluids: cold drinks, ice pops and soft foods soothe the throat
- Rest
- Skin care: moisturizer or calamine for itchy rash and peeling
Symptoms usually improve within 24 to 48 hours of starting antibiotics.
Complications
Prompt antibiotic treatment greatly reduces the risk of complications, which include:
- local: ear infections, sinusitis, peritonsillar abscess, swollen neck nodes with pus
- rheumatic fever: inflammation of the heart, joints, skin and brain 2 to 4 weeks after untreated strep throat; can permanently damage heart valves
- post-streptococcal glomerulonephritis: kidney inflammation causing dark urine and swelling 1 to 3 weeks after infection
- invasive group A strep: rare but serious infections of the blood, lungs, muscles (necrotizing fasciitis) or toxic shock syndrome
Prevention
- wash hands often
- do not share cups, utensils or towels
- cover coughs and sneezes
- keep children home until they have had at least 12 to 24 hours of antibiotics and are fever-free
- replace toothbrushes after treatment
There is no vaccine against group A strep yet.
Frequently asked questions
What does scarlet fever rash look like?
It is a red rash of tiny bumps that feels like sandpaper, starting on the neck and chest and spreading over the body. It is more intense in skin folds, and the cheeks look flushed with a pale ring around the mouth. It often peels as it fades.
Is scarlet fever contagious?
Yes. It spreads through droplets and shared items. People are contagious until they have taken antibiotics for 12 to 24 hours. Without treatment, they can remain contagious for weeks.
Can adults get scarlet fever?
Yes, though it is much less common than in children. Adults can catch it from children with strep infections. Symptoms and treatment are the same.
Is scarlet fever serious?
With antibiotics, scarlet fever is usually mild and clears quickly. Without treatment, it can lead to complications such as rheumatic fever, kidney inflammation and abscesses. Rarely, group A strep causes severe invasive infections.
How long does scarlet fever last?
With antibiotics, fever and sore throat usually improve within 1 to 2 days, and the rash fades within about a week. Peeling skin on the hands and feet may continue for several weeks.
Sources
This guide was written from current patient and clinical guidance, including:
- CDC: Scarlet Fever: All You Need to Know
- American Academy of Pediatrics (HealthyChildren.org): Scarlet Fever
- Infectious Diseases Society of America: Clinical Practice Guideline for Group A Streptococcal Pharyngitis
- NHS: Scarlet fever
- MedlinePlus: Scarlet fever