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Rash may be a symptom of bacterial or viral infection

  By: Les Riess, M.D.

Whether it's hives on the torso, red dots on the face, blisters around the mouth or itchy bumps on the arms, skin rashes can be bothersome and irritating. They can also be the symptom of a bacterial or viral infection.

A number of childhood diseases include a rash of some type. The good news is that as more vaccines become available, these diseases become less of a threat to a child's long-term health. This doesn't mean you should ignore a rash, however. Any rash should be monitored carefully, and may require a trip to the doctor's office for further evaluation.

Fifth disease, or erythema infectiosum, is a contagious viral illness. It is also known as “slapped cheek disease” because of the characteristic bright red rash that often appears on the face.

Initial symptoms of fifth disease resemble a mild flu, most often without a fever. About a week after the onset of flu-like symptoms, the facial rash may develop. It consists of fluid-filled lesions on the sides of the face and sometimes on the forehead and chin. This rash usually fades within two to five days. As the first rash is fading, a second rash on the neck, trunk, forearms, upper legs and buttocks, may start as round red spots, spreading to take on a lacy appearance. This rash may be itchy, and usually lasts a week or less.

Fifth disease is highly contagious, but only before the rash develops. By the time the rash appears, the child or adult is no longer contagious, and can safely return to school or work.

Chicken pox is caused by the virus varicella-zoster. An itchy rash characterized by areas of redness, each with a small blister in the center, is typically the first symptom of the illness. The rash usually starts on the scalp, armpits and groin area, and spreads in waves over the entire body. Blisters eventually rupture, and a crusty scab forms over each lesion.

Other symptoms of chicken pox include low-grade fever, sore throat and red eyes. Symptoms last for about two weeks.

Chicken pox is highly contagious. It is spread through inhalation of infected droplets or contact with the lesions of an infected person. A person remains contagious until all lesions have fully crusted over. There is a vaccine available for children age one and older.

Measles is caused by a paramyxovirus. On the third or fourth day of the illness, a person will develop a red rash on the face that spreads rapidly and lasts for about a week. A second rash, characterized by white spots on the gums and mouth may also develop.

Initial symptoms of measles include nasal congestion, cough, lethargy, high fever and eye redness, swelling and tearing. The illness typically lasts for a week to 10 days.

Most parents haven't experienced measles firsthand, because children are routinely vaccinated against the disease beginning at one year of age.

Scarlet fever, or scarlatina, is strep throat with a rash. One to two days after initial symptoms appear, a red rash with a sandpaper texture appears on the body. This rash will slough off in one to two weeks.

Other symptoms of this very contagious disease include sore throat, fever, headache, abdominal pain and swollen glands. The face appears flushed, but skin around the mouth is normal. Scarlet fever is spread through inhalation of infected droplets.

The rash itself is not serious, but complications can occur from the strep throat infection. The main concern is rheumatic fever, a serious illness that can damage the heart valves and cause long-term heart disease. Scarlet fever can be effectively treated with antibiotics. A person is no longer contagious 24 hours after beginning prescribed antibiotics, however, people who are not treated with antibiotics can continue to spread the disease for two to three weeks, even if they are experiencing no symptoms.

Impetigo is a superficial skin infection with streptococcal or staphylococcal bacteria. It begins as small blisters that rupture and leave red, open patches of skin. Typically a crust forms over the rash, which can be very itchy. The rash usually begins to heal within three to five days of first appearing.

Impetigo can occur anywhere on the body, but is most often found around the nose and mouth. The disease is very contagious, and can be spread to other parts of the body as well as other people.

The infection is often treated with topical or oral antibiotics. A person is no longer contagious after two to three days of antibiotic therapy.

There are two symptoms that, when present with a rash, are often signs of a more serious condition – petechiae and fever.

Petechiae are red dots on the skin that do not fade when pressure is applied. These dots represent bleeding from capillaries, leaving small temporary blood blisters on the skin. Petechiae can develop from a number of causes, including forceful coughing or vomiting.

When accompanied by fever, petechiae indicate cause for concern, and immediate medical evaluation. While most children will be diagnosed with a viral infection that requires no treatment, a small number (from two to seven percent) may have diseases that require immediate medical treatment such as meningitis.

Rashes aren't just an itchy inconvenience. Often they are a symptom of an underlying illness. Many conditions with rashes are most common in children and are usually not serious. Rashes should not be taken lightly, however. If you or your child develops a rash, monitor it closely. If the rash is characterized by red dots on the skin that do not fade with applied pressure, and is accompanied by a fever, seek medical attention as soon as possible, as these symptoms may be signs of a more serious condition.

Dr. Riess is a board certified family practice physician at Raiter Clinic.