Addressing fear of parasite infection

DEAR DR. ROACH » I’m crying out for help, and no one seems to care. I have a parasite. My sister has had a parasite in her for a couple years. She has been to several doctors and not one has tested her for parasites. The sad part is one of my babies also has it, I believe. He is 10. Please help us.

— Anon.

DEAR READER » I hear this concern from readers often, at least several times a year.

For anyone who suspects infection with a parasite, the first step is a careful history to evaluate for sources of exposure.

Documenting travel history and contact with other people or environments where a parasite may be picked up is paramount, as is a careful skin exam. Blood tests such as an eosinophil level — a type of blood cell that is increased in many parasitic diseases — can be helpful, and occasionally stool tests are of benefit. A few people need skin scrapings or even biopsy of skin lesions that can be evaluated by a laboratory to determine whether a parasite is present.

Very rarely, vitamin deficiencies can cause symptoms that resemble parasites, and treatment of the vitamin deficiency resolves the symptoms. Some people can develop similar symptoms after using recreational drugs, especially cocaine and methamphetamine, but these tend to be short-lived.

Often a parasite cannot be found. Sometimes, even if a parasite is not present, or is no longer present, biochemical changes in the body — as well as the attendant anxiety about having a parasite — can cause persistent symptoms. A physician needs to carefully evaluate the whole person and develop a trusting relationship that is necessary for successful treatment.

In patients where no evidence of current parasites is found despite a careful evaluation, treatment can still be extremely helpful. For some people, symptoms have been entirely relieved with medication treatment.

The most effective medications for treatment of persistent symptoms of parasites when no parasites can be found are the antipsychotic drugs, the same ones that are used for schizophrenia. This does NOT mean that the person with these symptoms has psychosis or schizophrenia. Many medications that are used in one condition have benefit on other conditions. For example, gabapentin was originally approved for seizures, but is most used for chronic pain, often as a result of damaged nerves.

Medication is effective, but sometimes it takes time to find the right one. With the right medication, symptoms slowly go away over a period of a few weeks to several months. Lifelong treatment is not necessary.