May 17, 2011
Is That Itching All In Your Mind?
A new study has found that there is no physical explanation for delusional infestations, and those patients who complained of being infected with bugs or eggs generally had a clean report on medical exams.
According to the Centers for Disease Control and Prevention, people who suffer from delusional infestation have also reported fatigue, joint pain, and short term memory loss.
In cases of delusional infestation, "patients often complain that the physician isn't examining their skin closely enough to see the infesting organisms," Dr. Mark Davis of the Mayo Clinic in Rochester, Minnesota, told Reuters Health.
"This study indicates that even when skin biopsies are obtained, and specimens of the organisms brought by the patients are carefully examined, there is no objective evidence of skin infestation," added Davis, who worked on the new study.
The researchers reviewed the cases of 108 patients who were diagnosed with delusional infestation at the Mayo Clinic between the years 2001 and 2007.
According to a report published in Archives of Dermatology, all of those patients believed they were infested with bugs, worms, or inanimate objects, and complained of different skin irritations.
Doctors did a biopsy on 80 of those patients to look more closely at the skin.
"This study is important for patients," the authors wrote in a statement. "Patients frequently believe that physicians are dismissive of their concerns and are not examining their skin closely enough, and therefore patients request that more testing be performed. This showed that biopsy results do not change a physician's clinical diagnosis of delusional infestation."
Over half of the biopsies did show dermatitis, a skin condition marked by inflammation and red and itchy skin. However, the researchers said they were unsure if that could be leading to patients' symptoms and beliefs that they were infested, or if their skin was inflamed due to them scratching.
A patient's symptoms in one case were partially explained by an underlying medical condition. The patient had rectal itching and tingling that turned into a crawling sensation. She was eventually diagnosed with the virus that causes herpes.
Davis said reports show that some patients with a delusional infestation may have other medical or psychiatric conditions.
The CDC has been researching how common delusional infestation is, as well as what type of people tend to report symptoms.
"It is an unexplained and debilitating illness of unknown cause," a CDC spokesperson told Reuters Health. "We recognize that...healthcare providers are perplexed and frustrated" and patients and their families are suffering, the spokesperson added.
Davis said it is important for doctors to take a patient's history and do a physical exam if they suspect delusional infestation but are not positive.
"If there is any possibility that the patient's complaints/concerns could be explained by anything other than delusional infestation, then all relevant tests should be done," he said in a statement.
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