Amid the economic downturn and slow growth for retail and outpatient medical-care services, pharmacy giants Walgreen Co. and CVS Caremark Corp. are rolling out specialized services at their in-store clinics, going beyond treatment of routine maladies.

Launched over the last four years to care for such simple ailments as ear and sinus infections, strep throat or pink eye, retail clinic operators now are training nurses to do specialized injections for such chronic conditions as osteoporosis and asthma.

In addition, they are offering treatments for advanced skin conditions that include removal of warts and skin tags or closing minor wounds. Care for minor "sprains and strains" also is being offered at some retailers, and pilot projects are under way for breathing treatments and special infusions of drugs derived from biotechnology.

"We want to create a health corner -- a real center that looks like you are walking into the doctor's office," Walgreens Chief Executive Gregory Wasson said of the Deerfield-based retailer's Take Care brand clinics.

There is a business reason for adding services. Walgreens and CVS have slowed their expansion of clinics and are instead making attempts to boost revenue by adding new lines of business in their clinics.

Typically staffed by advanced-degree nurses known as practitioners, most of the nation's more than 1,100 retail health clinics are open seven days a week, with no appointment needed.

The model has been greeted by health insurers, employers and consumer groups as one way to address the rising number of uninsured Americans, estimated at more than 46 million.

Retail clinics not only market themselves as a convenience, they also can be less expensive, providing a competitive threat to primary-care doctors and even specialists. Costs for services for those paying out-of-pocket at retail clinics generally runs $55 to $75 compared to $100 or more for a visit to a primary-care physician.

The physician community says consumers should look at the added services by clinics with skepticism, particularly when it comes to care for chronic ailments. And doctors say what a consumer may see as routine may turn out to be something worse.

"A sprain could be a muscle tear or a break, for crying out loud, so how does a [retail] clinic know when the patient comes in that they are going to treat a sprain?" said Dr. James Milam, president of the Illinois State Medical Society. "When my nurse gives an injection, I am here. The patient needs a regular doctor who has a history with the patient, knows their history, their family history and their illnesses."

But retailers say they are not going beyond "scope of practice" laws that regulate what nurse practitioners can and cannot do. The clinics are under physicians' supervision, though doctors usually are not on site.

"These are new services we were not providing that our customers asked us to provide," said Chip Phillips, president of MinuteClinic, a CVS subsidiary.

MinuteClinic said this spring that it added treatments for sprains, acne, wound care, motion sickness and testing for tuberculosis. And in Ohio, clinics are piloting a program to provide asthma patients with nebulizer breathing treatments.

In Florida, Walgreens has launched a pilot program in Tampa and Orlando to provide injections for patients with asthma and osteoporosis.

"A high percentage of new drug development is targeted toward biologics that will require clinical administration," Walgreens spokesman Michael Polzin said.

Wal-Mart Stores Inc., which works with several outside companies to staff clinics in its stores, has remained focused on "providing the stay-well and get-well services that we have always done, such as ear infections, sore throats and bladder infections," said spokeswoman Christi Gallagher, adding that the company is "always looking for ways to better serve our customers."