Strep throat and scarlet fever are contagious infections caused by a bacteria. They're most common among children aged 5-18 but can also affect adults.
Strep throat is an infection of the throat. An infected person will have the following symptoms:
Symptoms don't usually include a cough or a runny nose. Strep throat can turn into scarlet fever, in which case other symptoms develop:
- Red blotches on the skin, especially on the neck, chest, and stomach, that appear a few days after the initial symptoms and disappear within 2–7 days
- A red and swollen "strawberry" tongue
Symptoms usually appear 3–5 days after exposure to the bacteria. In rare cases, complications may develop in the kidneys, heart, joints, and ears if the infection remains untreated.
Causes and triggers
Strep throat and scarlet fever are caused by group A streptococcus bacteria. The bacteria are found in the nose and throat secretions of infected people. Transmission can occur in several ways:
- Through contact with the saliva of an infected person (e.g., a kiss)
- Through infected droplets coughed into the air by an infected person
- Through contact with objects that have been contaminated by an infected person
People with the disease are contagious for up to 24 hours after receiving treatment. If they don't receive treatment, they can be contagious for up to 3 weeks.
Strep throat and scarlet fever are treated with an antibiotic. It's essential to take the full course of antibiotics to ensure that the treatment is effective, even if symptoms have cleared up.
The following measures can help relieve symptoms:
- Get lots of rest
- Stay hydrated
- Eat soft foods
- Gargle with lukewarm salt water
- Take over-the-counter pain relief medications (e.g., Advil, Tylenol)
There is no vaccine against group A streptococcus. Infected people with symptoms are therefore advised to stay home until they've been on antibiotics for at least 24 hours. Hygiene measures such as the following can help limit the spread of the infection:
- Washing your hands
- Disinfecting surfaces
- Coughing into your elbow or a tissue
When should I see a health care professional?
Consult your health care provider if you have the following symptoms for more than 24 hours:
- Sore throat
- Swollen and tender lymph nodes in the neck
- Intense headache
Go to the emergency room if you have any of the following symptoms:
- You're passing very little urine and can't stay hydrated
- You have trouble opening your mouth or have more saliva than usual
- You have a seizure
Canadian Paediatric Society