NORTH HAVEN, Conn. — Boo and Riley are more than affectionate, protective family pets. To their owners, the specially trained dogs are a furry layer of security to sniff out peanut products and other life-threatening allergens.

The dogs' Connecticut owners are among many people nationwide turning to allergy-sniffing service dogs, who accompany their handlers to detect allergens and their residue at school, during social events and in other everyday activities.

As their popularity grows, though, some owners are having mixed success in convincing businesses, schools and those in charge of other public venues that the dogs must be accepted as service animals, just as dogs whose handlers' disabilities are more readily apparent.

They're already specifically recognized as medical service dogs in recent updates to the federal Americans with Disabilities Act, but some parents are taking it a step further by lobbying their local and state officials to update their regulations, too.

"The dog is just one way we can help our daughter have a more normal life," said Pam Minicucci of North Haven, whose 7-year-old daughter, Gianna, is constantly accompanied by her allergy-sniffing St. Bernard named Boo.

Minicucci asked Connecticut lawmakers this year to add allergy-sniffing dogs to the state statutes to mirror the ADA language, but the bill languished in a committee without full General Assembly action.

Gianna's allergy to peanut products, tree nuts and their residue in the air or on surfaces is so severe that even minuscule particles can trigger hives, itching and difficulty breathing that has sent her to the hospital several times. She carries an inhaler, wipes, Benadryl and EpiPen injectors everywhere in case she encounters anything to which she's allergic.

She and Boo get mixed reactions as they go to public venues and school, even though the dog wears a vest identifying it as a service animal.

"Our goal is for the dog to be with her everywhere she goes," Gianna's mother said. "I don't expect people to change their world for us, but I do expect them to allow us to protect our child in the way we need to."

State and federal agencies do not track the number of allergy-specific service dogs in the nation, but handlers and trainers say they're fielding more inquiries and orders in recent years. They attribute it to a growing awareness about the allergy-sniffing dogs and an increase in peanut allergies among many of today's children.

The federal Centers for Disease Control and Prevention estimates four of every 100 children have a food allergy, and says rates are highest among preschool-age children. It's also growing quickly: From 1997 to 2007, food allergies increased 18 percent among American children under 18 years old, though researchers haven't conclusively determined why.

Gianna Minicucci's allergies emerged when she was an infant and though she's grown out of some, others have remained so profound that her family decided the allergy-sniffing dog was a necessity.

Depending on the trainer and dog, the animals can cost between $10,000 and $20,000, including the training to teach them how to sniff out particular allergens and alert the handler with a specific signal. Often, that means abruptly sitting in place, often putting their own bodies between the allergic person and the allergen.

Owners tell of almost-daily incidents in which the dogs found something that their young handlers never would have spotted on their own.

In Gianna Minicucci's case, for instance, Boo once was so insistent on blocking her from walking down a non-food aisle in a big-box store that Gianna's mother questioned whether the dog was ill. When Pam Minicucci peered down below the shelves, she found the reason: a minuscule amount of peanut butter on a mouse trap far out of reach, but still close enough to potentially trigger Gianna's allergies.

The training for Boo and other allergy-sniffing dogs is similar to that of police dogs learning to track scents or dogs being trained to sniff out explosives for the military — which, in fact, inspired trainer Sherry Mers to work in the field after seeing a television show on bomb-sniffing dogs.

The Monument, Colo., woman launched Angel Service Dogs after getting a trained dog to help her 10-year-old daughter, Riley, avoid peanut products and residue from cross-contamination. Mers said the dogs may not be the right fit for every family, but that for children like her daughter, they literally can be life-savers.

"It's not just about the dog, it's not just about the allergy. It's about making sure your kid can exist in a world today so they don't have a disability," Mers said. "The reaction seems to be extremes: Either people are so accommodating they can't help but help you more, or they immediately go to this place of feeling that I'm violating their rights by trying to protect my child."

In a few cases, those disputes have attracted widespread attention.

In Indianapolis, for instance, a woman with a potentially life-threatening allergy to paprika got a specially trained dog to sniff out the substance. When she brought the dog to work, though, a co-worker who was allergic to dogs had an asthma attack.

The dog's owner filed a complaint with the U.S. Equal Employment Opportunity Commission after she was asked to leave the dog at home or take unpaid leave. The case is pending.

In other cases, though, the dogs have been welcomed.

In Ansonia, Conn., school officials have been so accommodating of 13-year-old Jeff Glazer's dog, Riley, that they installed special HEPA filters to the schools' air-circulation systems to ensure the yellow Labrador's presence wouldn't cause problems for children allergic to dogs.

Though Jeff's mother says they encounter some people who have concerns about the dog, they say others are supportive.

"Now that I have Riley, I can go to restaurants and movies and my friends' houses and not have to worry about it," Jeff said on a recent sunny afternoon, getting ready to stretch before a game with his traveling baseball team on a Middlebury sports field.

Before Jeff enters the dugout or touches the gear, though, Riley sniffs down everything for lingering residue from previous players who might have eaten peanut butter sandwiches, candy or other items. If Riley finds something, they use sanitary hand wipes —which Jeff and his family carry — to clean the surface thoroughly so he's not endangered.

Other than Riley's red service dog vest, he looks like any other pet accompanying his young master — exactly the kind of normalcy that once seemed out of reach.

"Riley really has changed his life. It's not a perfect world, it's not a perfect solution — we also have to use our heads and be aware of what's going on," said Jeff's mother, Lisa Glazer. "We still read labels, we still ask questions, we still go through the whole thing at restaurants, but Riley is our safety net."