Scarlet Fever Health Article

Definition

Scarlet fever is an infection caused by a streptococcus bacterium. It can be transmitted through the air or by physical contact and primarily affects children between four and eight years of age. In temperate climates, scarlet fever is most common during the late fall, winter, and early spring.

Scarlet fever is characterized by a sore throat, a fever of 103–104°F (39.4–40°C), and a sandpaper-like rash on reddened skin. If scarlet fever is untreated, such serious complications can develop; as rheumatic fever (a heart disease) or kidney inflammation (glomerulonephritis).

Description

Scarlet fever, or scarlatina, gets its name from the characteristic flush of the patient's skin, especially on the cheeks. Fever and sluggishness accompany a sore throat and raised rash that progressively covers much of the body. Symptoms usually begin within two to five days after a person is exposed. The fever usually subsides within a few days, and recovery is complete by two weeks. After the fever is gone, the skin on the face and body forms flakes, with the skin on the palms of the hands and soles of the feet peeling more dramatically.

Scarlet fever is highly contagious when the patient is in the early stages and is not being treated with antibiotics. It is spread by sneezing, coughing, or direct contact with an infected person. Early in the twentieth century, severe scarlet fever epidemics were common. As of the early 2000s, the disease is rare, partially because of the availability of antibiotics. However, antibiotics are not the entire reason, since the decline began before their widespread use. One theory is that the strain of bacteria that causes scarlet fever has become weaker over time.

Causes & symptoms

Scarlet fever is caused by Group A streptococcal bacteria (Streptococcus pyogenes). In addition to causing scarlet fever, Group A streptococci bacteria cause many different illnesses, such as strep throat, wound or skin infections, pneumonia, serious kidney infections, and toxic shock syndrome. The strain of streptococcus that causes scarlet fever is slightly different from the strain that causes most strep throats. The scarlet fever strain produces an erythrogenic toxin, which is what causes the skin to turn red.

The main symptoms and signs of scarlet fever are fever, sluggishness, sore throat, and a bumpy rash that blanches (turns white) when it's pressed. The rash appears first on the upper chest and spreads to the neck, abdomen, legs, arms, and in folds of skin such as under the arm or in the groin. The skin around the mouth tends to be pale while the cheeks are flushed. In children, the disease causes a "strawberry tongue," in which inflamed bumps on the tongue rise above a bright red coating. Strawberry tongue is rarely seen in adults. Finally, dark red lines (called Pastia's lines) may appear in the creases of skin folds.

Diagnosis

A medical practitioner must diagnose and treat scarlet fever. The doctor notes the symptoms and eliminates

the possibility of other diseases. Measles is a viral infection that is also associated with a fever and rash. However, scarlet fever can be distinguished from measles by the quality of the rash, the presence of a sore throat in scarlet fever, and the absence of the severe eye inflammation and runny nose that usually accompany measles.

Because scarlet fever may begin with a sore throat, the doctor will first determine if the problem is bacterial or viral in nature by checking for specific symptoms. For example, inflammation of the lymph nodes in the neck is typical in strep infections but not viral infections. On the other hand, cough, laryngitis, and stuffy nose tend to be associated with viral infections rather than strep infections.

Laboratory tests are necessary to make a definitive diagnosis of a strep infection and to distinguish a strep throat from a viral sore throat. One test that can be performed is a blood cell count. Bacterial infections are associated with an elevated white blood cell count. In viral infections, the white blood cell count is generally below normal. A throat culture can distinguish between a strep infection and a viral infection. A throat swab from the infected person is brushed over a nutrient gel containing red blood cells (a sheep blood agar plate) and incubated overnight. If streptococcal bacteria are present in the sample, they will break down the red blood cells and leave a clear zone in the gel surrounding the bacteria.

The doctor will also distinguish between a strep throat and scarlet fever. In a strep infection, the throat is sore and appears beefy and red. White spots appear on the tonsils. Lymph nodes under the jaw line may swell and become tender. These symptoms may or may not be present with scarlet fever. The main feature that distinguishes scarlet fever from a strep throat is the presence of the sandpapery red rash.