Understanding Scarlet Fever

Scarlet fever is a disease caused by exotoxin – a soluble protein released by a microorganisms such as bacteria, fungi, algae and protozoa – Streptococcus pyogenes. It causes damage to the host cell by destroying cells or disrupts the normal cellular metabolism.

Who gets scarlet fever?

Scarlet fever is common in children 5-15 years of age. It rarely affects people older than 18 years old.

Scarlet fever symptoms

Symptoms of scarlet fever include red sandpaper rashes. You can also have red lines in folds of skin around the groin, armpits, elbow, knees and neck. The tongue may also appear red and bumpy, usually covered with white coating early in the disease.

A person who has scarlet fever may appear flushed yet his/her mouth would appear pale. You can also have sore throat and may have difficulty swallowing. The lymph nodes glands would also be enlarged and tender to the touch. One could also have fever 38.3 C or higher, often accompanied by chills. Headache, nausea and vomiting are also some of the symptoms.

Causes of scarlet fever

Scarlet fever is caused by bacteria called Streptococcus pyogenes, or group A beta-hemolytic streptococcus. The bacteria cause strep throat. The strain of bacteria causing scarlet fever releases the toxins that cause the rash, the red lines, flushed face and red tongue.

The bacteria that cause scarlet fever may be transmitted from person to person by fluids from mouth and nose. The bacteria can get airborne when a person sneezes or coughs. The bacteria can also transfer from a person’s hand to objects that he/she touches. If you’re near an infected person, you may inhale the airborne bacteria.

If you touch something an infected person has touched and then touch your own nose or mouth, you could get the bacteria and have scarlet. The bacteria can also contaminate food especially milk, but this is not very common.

The time between and exposure and the actual illness (incubation) is about two to four days. If you don’t treat scarlet fever, it may be contagious for a few weeks, even after the sickness has passed.

When to seek medical advice

If your child has any of the following:

  • a sore throat with a fever,
  • a fever of 102 F (38.9 C) or higher (100 F for infants 6 months old or younger),
  • a sore throat that doesn’t go away within 24 to 48 hours,
  • a sore throat with swollen or tender glands in the neck,
  • a rash and difficulty swallowing or opening his or her mouth all the way.

You should see your doctor.

Tests and diagnosis

To determine the cause of your child’s sore throat and the rest of the initial symptoms, he will conduct the following:

  • 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.

Treatments and drugs

Your doctor may prescribe any of the following medications if he/she suspects scarlet fever:

  • Penicillin, in pill form or by injection
  • Amoxicillin (Amoxil, Trimox)
  • Azithromycin (Zithromax)
  • Clarithromycin (Biaxin)
  • Clindamycin (Cleocin)
  • A cephalosporin (Keflex, Ceclor)

Make sure that your child completes the full course prescribed by your doctor, even when your child is starting to feel better. If he doesn’t complete the full course, the medications may not do its job and totally eradicate the infection and increase the risk of having 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.


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