SAN DIEGO (CBS) – Tevita Alatini, a 7-year-old originally from Texas, died after developing a mysterious rash under his arm while vacationing with family July 9 at Camp Pendleton’s Lake O’Neill Recreational Park near San Diego.

Alatini was with his family when he developed a small rash that spread quickly. When he complained of a pain in his side, his family rushed him to the emergency room where he died a short time later.

A medical examiner in San Diego is waiting for tests to help determine Alatini’s cause of death.

“It sounds like an overwhelming strep or staph infection,” said Dr. William Thompson, who never treated Alatini but suspects the boy died from a flesh eating bacteria that devours tissue and muscle after entering the skin through a small cut.

Dr. Thompson says he’s surprised by the number of patients he has treated in the last few years with the flesh eating bacteria. Dr. Thompson says, just like Alatini, it starts with an aggressive rash and leads to organ failure.

“It’s disconcerting because the morbidity is so high with these patients,” said Thompson.

Thompson says the staph or strep that causes the flesh eating bacteria likely wasn’t picked up in the lake.

Alatini’s uncle Sione Niko spoke by phone with CBS2 and KCAL9 reporter Stacey Butler and said his nephew never entered the water.

“He was just laying there, not feeling well and he started to feel really sick,” said Niko.

Why most people are resistant to the infection and others aren’t remains a mystery.

In a statement, the San Diego medical examiner’s office said Alatini had a severe infection. The exact cause of death remains undetermined pending further testing.