Scarlet fever, also known as scarlatina, is a disease caused by a toxin released by the bacteria Streptococcus pyogenes, the same organism that causes strep throat. Scarlet fever mainly affects children and is characterized by a distinctive pink-red rash.
It is less common than it used to be, but there are occasional, significant outbreaks.
What is scarlet fever?
Although the term scarlatina can be used interchangeably with scarlet fever, scarlatina is more commonly used to refer to the less acute form of scarlet fever.
Scarlet fever used to be considered a serious childhood illness but modern antibiotics have made it a much rarer and less threatening disease. However, if left untreated, scarlet fever can sometimes lead to serious complications.
However, it is important to be aware of the signs and symptoms, so that it can be caught early and treated with antibiotics as soon as possible.
Fast facts on scarlet fever
Here are some key points about scarlet fever. More detail and supporting information is in the main article.
Causes of scarlet fever
Scarlet fever is more common in children aged from 5-15.
Scarlet fever is caused by the bacterium Streptococcus pyogenes, or group A beta-hemolytic streptococcus. This is the same bacterium that causes strep throat.
When the bacteria release toxins, scarlet fever symptoms occur.
Scarlet fever transmits from human-to-human by fluids from the mouth and nose. When an infected individual coughs or sneezes, the bacteria become airborne in droplets of water and can be inhaled.
The bacteria can land on surfaces, such as drinking glasses, work surfaces, and doorknobs, and infect people who touch them with their hands and then touch their own nose or mouth. The bacteria may also be inhaled.
If someone touches the skin of an individual with a streptococcal skin infection, there is a risk of becoming infected. People who share towels, baths, clothes, or bed linen with an infected person are at risk.
A person with scarlet fever who is not treated may be contagious for several weeks, even after symptoms have gone. Additionally, some individuals can carry the infection and be contagious, without ever showing any symptoms - only people who are susceptible to the toxins released by streptococcal bacteria develop symptoms.
These factors make it harder for individuals to know whether they have been exposed.
Although much less common, people may become infected by touching or consuming contaminated food, especially milk.
Symptoms of scarlet fever
Signs and symptoms generally appear about 1-4 days after initial infection. The first symptoms of scarlet fever are usually:
- A very sore and red throat (sometimes with white or yellowish patches).
- A fever of 101 Fahrenheit (38.3 Celsius) or higher, frequently with chills. 12-48 hours later, the rash will appear.
- Rash - red blotches appear on the skin; they then turn into a fine pink-red rash that looks like sunburn. The skin feels rough like sandpaper when touched.
The rash spreads to the ears, neck, elbows, inner thighs and groin, chest, and some other parts of the body. Although the rash does not usually appear on the face, the patient's cheeks will become flushed, and the area around their mouth becomes pale.
If a glass is pressed on the skin, the rash will turn white (blanche).
After about 6 days, the rash usually fades. In milder cases, such as scarlatina, the rash may be the only symptom.
Other potential symptoms of scarlet fever include:
Stomachache is a common symptom of scarlet fever.
- Difficulty swallowing
- General malaise
- Loss of appetite
- Pastia's lines - broken blood vessels in the folds of the body, for example, the armpits, groin, elbows, knees, and neck
- Swollen neck glands (lymph nodes) that are tender to the touch
- A white coating forms on the tongue - this eventually peels away leaving a strawberry tongue; the tongue is red and swollen
If the patient has other symptoms, such as severe muscle aches, vomiting, or diarrhea, the doctor will need to rule out other possible causes, such as toxic shock syndrome.
The skin of the hands and feet will peel for up to 6 weeks after the rash has gone.
Risk factors for scarlet fever
- Children aged 5-15 have a higher risk of developing scarlet fever compared with other age groups. Around 80 percent of cases occur in children under 10.
- Close contact - the strep bacteria can spread more easily among people in close contact, for instance at school, home, or work.
Diagnosing scarlet fever
The characteristic rash and symptoms usually make it fairly easy for a doctor to diagnose scarlet fever. The doctor may take a throat swab to determine which bacteria caused the infection. Sometimes a blood test is also ordered.
In a rapid DNA test, a throat swab is taken. Results are returned in less than 24 hours.
Treatments for scarlet fever
The majority of mild cases of scarlet fever resolve themselves within a week without treatment, but it is important to get treatment as this will accelerate recovery and reduce the risk of complications. Patients generally recover about 4-5 days after treatment begins.
Antibiotics - a 10-day course of antibiotics is the most common treatment for scarlet fever. This normally involves taking oral penicillin. Patients who are allergic to penicillin may take erythromycin instead. Patients are advised to stay at home during the course of the antibiotic treatment.
The fever will usually go within 12-24 hours of taking the first antibiotic medication.
A child with scarlet fever may be prescribed one of the following antibiotics:
- Penicillin, in pill form or by injection
- Amoxicillin (Amoxil, Trimox)
- Azithromycin (Zithromax)
- Clarithromycin (Biaxin)
- Clindamycin (Cleocin)
- A cephalosporin such as cephalexin (Keflex)
It is important to take the full course of antibiotics, even if symptoms go away before it is finished. Otherwise, the infection may not be completely eradicated, raising the risk of subsequent post-strep disorders.
If the patient does not start feeling better within 24-48 hours after starting the antibiotic treatment, a doctor should be called.
Within 24 hours of starting the antibiotics, the patient will no longer be contagious.
How to soothe scarlet fever at home
Although a visit to the doctors is essential, there are some ways to soothe symptoms at home. It is important to drink plenty of liquids, especially if there is no appetite, and the environment should be kept cool.
Tylenol (acetaminophen) may help relieve aches and pains, as well as bringing the fever down.
Calamine lotion can help with itchy skin.
Possible complications of scarlet fever
In the majority of cases, there are no complications; however, the following can occur:
- Ear infection, including otitis media.
- Throat abscess - a pus-filled sac in the throat.
- Inflammation of the kidney(s) - post-streptococcal glomerulonephritis, resulting from certain immune responses to strep bacteria. In some cases, there may be long-term kidney disease.
- Rheumatic fever.
- Some skin infections.
The following complications are possible, but very rare:
- Acute kidney (renal) failure.
- Meningitis - inflammation of the membranes that surround the brain and spinal cord.
- Necrotizing fasciitis - commonly known as flesh-eating disease.
- Toxic shock syndrome.
- Endocarditis - infection of the heart's inner lining.
- Infection of the bone and bone marrow (osteomyelitis).
- PANDAS (Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections) - some research has indicated that strep bacterial infection may trigger an autoimmune response that exacerbates symptoms of certain childhood disorders, such as OCD (obsessive-compulsive disorder), Tourette syndrome, and ADHD (attention deficit hyperactivity disorder). The increase in symptoms does not usually last for more than a few weeks or months.
Preventing scarlet fever
The best prevention strategies for scarlet fever, as with all highly infectious diseases, are:
- Isolation - keep the patient away from other people. Keep the child away from school.
- Handkerchiefs or tissues that the patient has used should be washed or disposed of immediately. If you have touched any of these wash your hands thoroughly with warm water and soap.
- Handwashing - the patient, usually a child, should be taught to wash their hands thoroughly and frequently.
- Dining utensils - do not share drinking glasses or eating utensils with the patient.
- Coughing and sneezing - the patient should be taught to cover their mouth and nose when coughing and sneezing. This should be done into a tissue or handkerchief. If one is not available, it is better to cough or sneeze into the inside of the elbow - coughing into one's hands raises the risk of contaminating things when they are touched.