SCHOOLS SEE RISE IN `FIFTH DISEASE'.

Byline: Patricia Farrell Aidem Daily News Staff Writer

Contagious ``fifth disease,'' characterized by a distinctive rash that starts on the face and spreads to the limbs, is making the rounds among Santa Clarita schoolchildren, health and school officials said Monday.

Fifth - technically erythema infectiosum - in most cases is not serious, except in a few pregnant women and patients with immune deficiencies, said Dr. David Dassey, deputy director of the acute communicable disease control program of the Los Angeles County Health Services Department.

Its name denotes its rank among the five major childhood rash diseases - measles, scarlet fever, rubella, chicken pox and fifth.

A small outbreak at Charles Helmers School in Valencia prompted officials there to notify parents last week to keep infected children home, particularly because two second-grade teachers are pregnant, Principal Candace Clark said.

Clark said she also wanted to protect any school volunteers and to warn any mothers who might be pregnant.

``I think it's good for parents to be aware,'' Clark said. ``Not a lot of people know about it, and parents may have no idea if their children have it.''

Some possible cases also have been reported at Mountainview School, which shared the Helmers campus until Monday, when the new school opened.

Valencia pediatrician Lorraine Stern said she has seen two or three young patients a day over the last several weeks. In adults, fifth might not yield a rash, but usually causes joint pain, she said, adding that the disease tends to spread during the springtime.

Fifth generally begins with cold-like symptoms and a ``slapped face'' rash, a reddening of the cheeks, Stern said. It can be accompanied by a low-grade fever, and the rash tends to spread to the extremities, recurring for as long as a three-week period.

Typically, there is no treatment for the disease because it is so mild, Stern said.

``It's a minor infection,'' she said. ``Probably by the time they break out they're not contagious.''

In rare cases, fifth can be life-threatening to a fetus in the first half of pregnancy if the mother contracts the disease, Dassey said.

Pregnant women who are exposed to fifth should contact their obstetricians, Stern said.

Fifth is more serious among people with immune deficiencies, including AIDS, Dassey said. The virus infects the bone marrow and hampers the production of blood cells.