Roseola infantum

Measles and chickenpox are pretty much household words. Other contagious rash-causing diseases of childhood, fifth disease, roseola, scarlet fever, and impetigo, may not have the same amount of name recognition, but lack of fame doesn't mean that they don't cause problems!

Fifth Disease (Erythema Infectiosum)

"I used to ask my students, 'Who was Dr. Fifth?'" says Paul F. Wehrle, M.D., professor emeritus in pediatrics at the University of Southern California. "They used to come up with some really interesting answers."

The real answer, however, is that there was no Dr. Fifth. The common name for erythema infectiosum came from its fifth position on a list developed in the early 1900's of childhood rash diseases. (Measles topped the list, followed by scarlet fever and rubella. Number four -- Filatow-Dukes disease -- turned out to be a mild form of scarlet fever.)

Those medical students weren't alone. Many people have never heard of fifth disease even though most have been infected with it.

Fifth disease doesn't make a lasting impression," says Thomas J. Torok, M.D., a specialist on erythema infectiosum with the national Centers for Disease Control. He explains that in many children the symptoms are mild, and in approximately 20 percent of those infected, there are no symptoms at all. "It's so mild, most mothers never remember that their children had it," he says.

Usually, the first symptoms of fifth disease -- low-grade fever and general feeling of malasise -- are indistinguishable from a mild case of the flu. Then, anywhere from seven to 10 days later, the rash will appear.

If anything about fifth disease can make a lasting impression, it's the distinctive "slapped cheek" appearance of the facial rash. The rash then spreads to the trunk and extremities, frequently developing a lacy pattern. The rash generally fades within two weeks, but external factors such as sun exposure, bathing, excitement, or exercise can cause it to reappear several weeks later.

Caused by the human parvovirus B19, there is no oral drug treatment for fifth disease. If the rash itches, "plain calamine lotion and cool water should provide enough relief," says John Lower, M.D., a pediatrician in private practice in Wheaton, MD.

Most cases of fifth disease occur in children 5 to 14 years old, and outbreaks are more common during winter and spring. Once infected, a person has lifelong immunity.

For adults who passed through childhood without catching fifth disease, symptoms can be more severe, including arthritis and arthralgias (joint pains). Occasionally, these painful symptoms can last for years.

While not a serious infection among the general population, fifth disease can cause a life-threatening anemic reaction in certain people, such as those with sickle cell anemia.

According to CDC, fifth disease may increase the risk of miscarriage if a woman is infected during the first 20 weeks of pregnancy.

"The risk [of miscarriage] is small," says CDC's Torok. He explains that most adults are immune, since they were infected as children. In addition, even in those mothers who aren't immune, an infection doesn't automatically cause a miscarriage. There is no evidence that fifth disease causes any birth defects, according to CDC.

"More than 90 percent of women infected deliver healthy, term babies," says Torok.

Some physicians have recommended that if an outbreak of fifth disease occurs at a school, pregnant school employees should stay home for two to three weeks after the last case has been diagnosed.

"That's a totally illogical reaction," says Torok. "First of all, outbreaks can last for months. And second, the disease is in the community, not just the school. Staying away from the school accomplishes nothing."

Lowe, agrees, explaining that by the time the rash breaks out, the child is no longer contagious.

Roseola Infantum (Exanthem Subitum)

Roseola commonly starts with a high fever, frequently as high as 40 degrees Celsius (104 [degrees] Fahrenheit). The fever usually lasts for three to five days, although the very high temperatures may be intermittent. Roseola's high fevers are a common cause of febrile (feverish) convulsions during the first two years of life.

Although a convulsion can be quite frightening, especially for the parents, "they're not harmful," says Lowe. "A convulsion with fever is just the response of the immature brain to the rapid changes in temperature."

Except for the convulsions, children usually don't appear as sick as might be expected with such a high fever, says Lowe. On the fourth or fifth day the temperature drops to normal and then the rash suddenly appears.

"It's not like other rashes where first a few spots appear and slowly the rest of the body gets covered," says Lowe. "This pops up everywhere all at once, and disappears just as quickly."

Although the rash can last as long as two days, sometimes it can come and go in only a few hours. "If the baby gets it during the night, the parents may miss it completely," says Lowe. Also known as baby measles, 82 percent of all roseola cases occur in infants 6 to 24 months old.

The cause of roseola is herpes virus-6. There is no cure except time; treatment is directed to alleviating the symptoms. "Push fluids," says Lowe. He explains that a high fever increases the risk of dehydration.

To reduce the fever, acetaminophen, not aspirin, should be used, says Lowe.

Scarlet Fever

A case of scarlet fever used to mean quarantines by public health officials, months of convalescence, and, sometimes, serious and permanent disabilities, even death.

Then two things -- one from human ingenuity, the other from natural evolution -- changed the face of the disease.

The first was the discovery in 1928 of penicillin; the second, the strains of Group A streptococcus responsible for scarlet fever becoming less virulent in the 1930s and 40s.

Today, treatment with penicillin or other antibiotics such as erythomycin can stop the disease before some of the characteristic symptoms -- especially the bright red "strawberry tongue" -- appear.

In addition, even though some strains of Group A strep are becoming more virulent, so far the strains responsible for scarlet fever aren't, and cases of scarlet fever are "mostly still mild," says Bascom Anthony, M.D., Director of FDA's division of bacterial products.

"Scarlet fever is basically strep throat with a rash," says Rosemary Roberts, M.D., a pediatrician with FDA's division of anti-infective drug products. The infection usually starts with a sudden, high fever of about 40 [degrees] C (104 [degrees] F), sore throat, headache, severe stomach pains, and vomiting. The pharynx and tonsils are beefy red. Sometime between 12 and 48 hours later the rash appears below the ears and on the chest and underarms. Eventually, it may spread to the abdomen, arms, legs, and face.

Without treatment, the rash may give the skin a rough texture frequently described by doctors as "sunburn with goose pimples" or "alligator skin." The strawberry tongue usually appears on day four or five. If allowed to run its course, the fever would last about six days and the rash for about a week. Since the modern-day scarlet fever is relatively mild, serious complications rarely occur.

One symptom, peeling skin, especially on the hand and feet, usually can't be stopped even with antibiotics. The peeling starts about 10 days after infection and may continue for six weeks.

Infection results in lifelong immunity, but because there are so many strains of Group A strep, a person can get scarlet fever more than once.

Although the symptoms are usually clear-cut from the beginning, diagnosis should not be based on clinical signs alone, says Lowe. He explains that a throat culture is necessary "to differentiate [the cause] from other things such as toxic shock syndrome and Kawasaki disease." (Toxic shock syndrome is caused by Staphylococcus aureus bacteria; the cause of Kawasaki disease is unknown. Both require different courses of treatment than scarlet fever.)

Impetigo

Impetigo is the most common skin infection in children. "It spreads like wildfire in kids, because they're always touching each other," says Lowe.

Unlike the other three rashes, which are caused by internal infections, the impetigo rash is caused by an external infection with Staphylococcus aureus, Streptococcus pyogenes, or a combination of the two bacteria. Thin-walled blisters usually result when the culprit is staphylococci; strep usually causes thick, crusted lesions.

Until the early 1980s, the medical community considered strep the main cause of impetigo. Although several recent studies have suggested that staphylococci may be winning out as the major cause, "impetigo is still a mixed bag," says FDA's Anthony. "Clearly, there are many cases that are still caused by strep."

Because many strains of staphylococcus are resistant to penicillin, doctors usually prescribe alternative antibiotics.

A small, localized infection can be treated with the antibiotic ointment mupirocin. FDA's Roberts cautions, however, that the ointment must be put on every single blister or lesion. "If the rash is spreading all over the body," she says, "a systemic [oral antibiotic] would be better."

In addition to antibiotic treatment, a few simple steps can help stop the spread of the infection, says Andrew Gellady, M.D., a spokesman for the American Academy of Pediatrics. "Make sure no one shares a towel, and wash sheets and towels in hot water," he says.

There is no reason to pop the blisters or scrub the lesions, says Gellady. "Leave the rash alone."

Because there are several strains of both staph and strep, a person can get impetigo more than once.

Though they may seem severe and even scary to parents when they occur, in retrospect these diseases are often remembered as uncomfortable but controllable and fortunately fleeting childhood experiences.

COPYRIGHT 1993 Pediatrics for Parents, Inc.
COPYRIGHT 2004 Gale Group