Sharmaine Parks leaves the Medstar Georgetown University Hospital's Kids Mobile Medical Clinic with her sons after an appointment Monday. (Toni L. Sandys/The Washington Post)

Whether she’s had a headache, a sinus infection or a rash, Sharmaine Parks of Northeast Washington knew the white van would always be there.

For nearly two decades, the 21-year-old has used the mobile clinic that would park around the corner from her East Capitol Street home every week. Parks, who said she has health insurance but no primary care physician, even visited the van for checkups while she was pregnant with her two children. And on Monday she took her 2- and 3-year-old boys there to see the traveling group of pediatricians because the boys had a mysterious, itchy rash.

“They’re always right about everything,” she said of the doctors. “And they help us.”

The KIDS Mobile Medical Clinic/Ronald McDonald Care Mobile has been riding through the streets of Washington for 20 years. Run by the department of community pediatrics at Medstar Georgetown University Hospital, the van has treated 5,000 District children, according to hospital figures.

That’s 50,000 patient visits, said Matthew Levy, a pediatrician and medical director of the Kids Mobile Medical Clinic.

“We’re part of the community,” he said.

The van targets some of the District’s most-impoverished neighborhoods and reaches children who often lack access to doctors and health services.

Levy said the clinic examines all the barriers to medical care and helps residents overcome them, no matter where they live. Whether it’s the clinic’s monthly ophthalmologist visits, free glasses for the uninsured, immunization or a limited pharmacy, Levy said, residents continue to turn to what they affectionately call “the van” year after year.

“There’s something about our program that’s unique and special, and our families know that — that’s why they come back,” Levy said. “We treat them with the utmost respect, and we care about their success.”

And there are plans to expand. Soon dental and nutritional care will be available at the van.

Four days a week, the mobile clinic travels to Lincoln Heights, the Richardson Dwellings, Phelps High School, 12th and G Streets Southeast and Martin Luther King Greenleaf Recreation Center. And the doctors — who also see people up to the age of 21 — are on call during the evenings and weekends.

Jamese Hines always saw the van outside her Lincoln Heights home, but she never knew what it was.

“I would always say, ‘I wonder what that is over there,’ but I didn’t want to be too nosy,” said Hines, who took her 1-year-old daughter, Aaliyah, to the clinic for the first time Monday. “I would come sit by the bus stop and wonder what it is — so one day I came up here and asked.”

Hines said the van was “quick, and they get you in fast.”

“They don’t have you sitting waiting at the doctor’s office for 20, 30 hours,” she added.

“I come here all the time,” said Natasha Smith, 38, as she waited for instructions from a medical student about how often to give her 6-year-old medicine. “It helps me, it’s real convenient and they’re really nice and lovely people.”

Ana Caskin, a pediatrician who began her medical career seeing patients on the van shortly after it started in the 1990s, said the mobile clinic was successful because of the people behind it.

“It’s a testament to how much it was needed,” she said.

The mobile clinic’s home is a 40-foot-long white truck, and inside it looks a lot like any busy pediatrician’s office.

About 10 to 20 patients a day check in at the front with the driver, then get weighed in one corner with a nurse and examined in a private room in the front or back of the van. And in the middle of it all there’s the wall of full of baby photos that Levy said reminds them “why we’re here.”

“We’re hoping to celebrate another 20 years,” Levy added. “And to continue to build.”