Scarlet fever, or scarlatina, is an illness that brings on a rash covering most of the body, a strawberry-like appearance of the tongue and usually a high fever. The most common source of scarlet fever is one form of a common bacterial infection known as strep throat. Therefore, a sore throat and other signs and symptoms of a typical strep throat infection almost always accompany scarlet fever.
Infrequent sources of scarlet fever are related bacterial infections affecting other organ systems.
Scarlet fever rarely affects people older than 18 and is most common in children 5 to 15 years of age. Although scarlet fever was once considered a serious childhood illness, antibiotic treatments have made it less threatening.
Nonetheless, if left untreated, scarlet fever (like strep throat) can result in more serious conditions that affect the heart, kidneys and other parts of the body.
If your child has scarlet fever, he or she may experience these common signs and symptoms:
- Red rash that looks like a sunburn and feels like sandpaper
- Red lines (Pastia’s lines) in folds of skin around the groin, armpits, elbows, knees and neck
- Strawberry-like red and bumpy appearance of the tongue, often covered with a white coating early in the disease
- Flushed face with paleness around the mouth
- Fever of 101 degrees Fahrenheit or higher, often with chills
- Very sore and red throat, sometimes with white or yellowish patches
- Difficulty swallowing
- Enlarged glands in the neck (lymph nodes) that are tender to the touch
- Nausea or vomiting
The sore throat, enlarged lymph nodes and fever are likely to appear first, while the “scarlet” signs and symptoms of scarlet fever usually appear on the second day of illness. If your child has scarlet fever, the rash will most likely begin on his or her chest and spread to the neck, trunk, arms and legs. The rash won’t appear on your child’s face, palms of the hands or soles of the feet.
The rash and the redness in the face and tongue usually last about a week. After these scarlet fever symptoms have subsided, the skin affected by the rash often peels.
A bacterium called Streptococcus pyogenes, or group A beta-hemolytic streptococcus causes scarlet fever. This is the same bacterial infection that causes strep throat, but the strain of bacteria causing scarlet fever releases toxins that produce the rash, Pastia’s lines, flushed face and red tongue.
Strep bacteria that cause scarlet fever spread from one person to another by fluids from the mouth and nose. If an infected person coughs or sneezes, the bacteria can become airborne, or the bacteria may be present on things the person touches — a drinking glass or a doorknob. If you’re in proximity to an infected person, you may inhale airborne bacteria. If you touch something an infected person has touched and then touch your own nose or mouth, you could pick up the bacteria.
The incubation period — the time between exposure and illness — is usually two to four days. If scarlet fever isn’t treated, a person may be contagious for a few weeks even after the illness itself has passed. And someone may carry scarlet fever strep bacteria without being sick. Therefore, it’s difficult to know if you’ve been exposed.
Scarlet fever strep bacteria can also contaminate food, especially milk, but this mode of transmission isn’t as common.
Rare causes of scarlet fever
Rare causes of scarlet fever are other strains of Streptococcus pyogenes associated with either a skin infection (impetigo) or a uterine infection contracted during childbirth. These cases result in the characteristic fever, rash and other “scarlet” symptoms but not signs and symptoms associated with a throat infection.
Children 5 to 15 years of age are more likely than other people to get scarlet fever.
Scarlet fever strep bacteria spread more easily among people in close contact. If a child carries the bacteria, the disease can spread easily among family members or schoolmates.
Your doctor will conduct an exam to determine the cause of your child’s sore throat, rash and other symptoms. He or she will:
- Look at the condition of your child’s throat, tonsils and tongue
- Feel your child’s neck to determine if lymph nodes are enlarged
- Assess the appearance and texture of the rash
If your doctor suspects strep as the cause of your child’s illness, he or she will also swab the back of your child’s throat to collect material that may harbor strep bacteria. Tests for the strep bacterium are important because a number of conditions can cause the signs and symptoms of scarlet fever, and these illnesses may require different treatments. If there are no strep bacteria, then some other factor is causing the illness. Your doctor may order one or more of the following laboratory tests:
- Throat culture. The sample from your child’s throat is examined in a laboratory test in which the bacteria can thrive. Although this is a very reliable test, the results may take as long as two days.
- Rapid antigen test. Your doctor may also order a rapid antigen test, sometimes called a rapid strep test, which can detect foreign proteins (antigens) associated with strep bacteria infection. This test can be completed during a visit to your doctor’s office. This test is less reliable than a throat culture. If a rapid antigen test is negative, your doctor will probably order the throat culture to ensure an accurate diagnosis.
- Rapid DNA test. Your doctor may also be able to order a relatively new rapid test that uses DNA technology to detect strep bacteria from a throat swab in a day or less. These tests are at least as accurate as throat cultures, and the results are available sooner.
Scarlet fever rarely results in serious complications, particularly if promptly and appropriately treated with antibiotics. But post-scarlet fever disorders may occur. These include:
- Rheumatic fever. Rheumatic fever is an inflammatory disease that can affect the heart, joints, skin and nervous system. Long-term effects may include damage to heart valves; other heart disorders; and a syndrome called Sydenham’s chorea, which causes emotional instability, muscle weakness and jerky movements of the hands, feet and face. Appropriate treatment of strep bacteria infection greatly reduces the risk of rheumatic fever.
- Poststreptococcal glomerulonephritis. Poststreptococcal glomerulonephritis is inflammation of the kidneys that results from certain byproducts of strep bacteria infection. This disorder may cause long-term kidney disease.
- Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS). In children who have neuropsychiatric disorders, such as obsessive-compulsive disorder and Tourette syndrome, some researchers believe strep bacteria infection may cause or are associated with an autoimmune disorder that significantly exacerbates psychiatric symptoms.
Other complications that may result from untreated scarlet fever include:
- Bacterial infection of the blood (bacteremia)
- Ear infection (otitis media)
- Inflammation of the membranes and fluid that surround the brain and spinal cord (meningitis)
- Infection of the bone behind the ear (mastoiditis)
- Infection of the heart’s inner lining (endocarditis)
- Inflammation of mucous membranes and buildup of fluids in the sinuses (sinusitis
- Pus-filled sac (abscess) in the throat
- Skin infections
If your child has scarlet fever, your doctor will likely prescribe an antibiotic medication. Examples include:
- Penicillin, in pill form or by injection
- Amoxicillin (Amoxil, Trimox)
- Azithromycin (Zithromax)
- Clarithromycin (Biaxin)
- Clindamycin (Cleocin)
- A cephalosporin (Keflex, Ceclor)
Makesure your child completes the full course of prescribed antibiotics as directed by your physician, even when your child is feeling better. Failure to follow the treatment guidelines may not completely eradicate the infection and will increase your child’s risk of developing post-strep disorders.
If he or she isn’t feeling better within 24 to 48 hours after starting the medication, call your doctor.
Your child will no longer be contagious after 24 hours on antibiotics and can return to school when he or she is feeling better and no longer has a fever.
The best prevention strategies for scarlet fever are the same as the standard precautions against infections. Teach your child to practice the following healthy habits:
- Wash your hands. Your child should learn to wash his or her hands thoroughly with warm soapy water.
- Don’t share dining utensils. He or she shouldn’t share drinking glasses or eating utensils with friends or classmates.
- Cover your mouth and nose. Your child should learn to cover his or her mouth and nose when coughing and sneezing to prevent the potential spread of bacteria.
If your child has scarlet fever, wash his or her drinking glasses, utensils and, if possible, toys in hot soapy water or in a dishwasher.
You can take a number of steps to reduce your child’s discomfort and pain.
- Treat fever and pain. Consult your doctor about using ibuprofen (Advil, Motrin, others) or acetaminophen (Tylenol, others) to control the fever and minimize throat pain. You may also put a lukewarm cloth on your child’s forehead to cool the fever if he or she doesn’t have chills.
- Provide adequate fluids. Give your child plenty of water to keep the throat moist and prevent dehydration.
- Prepare a saltwater gargle. If your child is able to gargle water, give him or her salty water to gargle and then spit out. This may ease the throat pain.
- Humidify the air. Use a cool-air humidifier to eliminate dry air that may further irritate a sore throat.
- Offer lozenges. Children older than age 4 can suck on lozenges to relieve a sore throat.
- Provide comforting foods. Warm liquids such as soup and cold treats like popsicles can soothe a sore throat.
- Avoid irritants. Keep your home free from cigarette smoke and cleaning products that can irritate the throat.