Pica is the persistent craving and compulsive eating of non-food substances.
The puzzling phenomenon of pica has been recognized and described since ancient times. Pica has been observed in ethnic groups worldwide, in both primitive and modernized cultures, in both sexes, and in all age groups. The word pica comes from the Latin name for magpie, a bird known for its unusual and indiscriminate eating habits. In addition to humans, pica has been observed in other animals, including the chimpanzee.
True pica affects people of all ages, although it is more common in children. There are some regional variations concerning specific substances. For example, eating clay is more prevalent among women in the American southeast than in other areas of the country. Adolescents may chew ice due to peer pressure or because they are deficient in iron. Without a blood test for serum iron, there is no way to differentiate these causes.
Causes and symptoms
Pica in humans has many different subgroups, defined by the substance that is ingested. Some of the most commonly described types of pica are eating earth, soil, or clay (geophagia); ice (pagophagia); and starch (amylophagia). However, pica involving dozens of other substances, including cigarette butts and ashes, hair, paint chips, and paper have also been reported.
Although pica can occur in individuals of any background, a higher incidence of pica is associated with:
- developmental disabilities
- mental retardation
- psychiatric disease and autism
- early childhood (under age three)
- poor nutrition or low blood levels of iron and other minerals
- certain cultural or religious traditions
When to call the doctor
A health care professional should be consulted whenever a child over the age of three repeatedly ingests non-food substances for a period over one month. The behavior might be merely habitual, but it can become a compulsion that needs treatment.
In order for the diagnosis of pica to be made, there must be a history of persistent consumption of a non-food substance continuing for a minimum period of one month. Infants and toddlers are typically excluded from this diagnosis since mouthing objects is a normal developmental behavior at that age. Individuals with mental retardation who function at or below an approximate cognitive level of 18 months may also be exempt from this diagnosis.
Pica is most often diagnosed when a report of such behaviors can be provided by an individual or documented by another person. In other cases, pica is diagnosed after studies have been performed to assess the presenting symptoms. For example, imaging studies ordered to assess severe gastrointestinal complaints may reveal intestinal blockage with an opaque substance; such a finding is suggestive of pica. Biopsy of intestinal contents can also reveal findings, such as parasitic infection, consistent with pica. Pica may also be suspected if abnormal levels of certain minerals or chemicals are detected in the blood.
Treatment of pica will often depend on the cause and type of pica. Conventional medical treatment may be appropriate in certain situations. For example, supplementation with iron-containing vitamins has been shown to cause the unusual cravings to subside in some iron-deficient people.
Medical complications and health threats, including high lead levels, bowel perforation or intestinal obstruction, will require additional medical management, beyond addressing the underlying issue of pica.
Because most cases of pica do not have an obvious medical cause, treatment with counseling, education, and nutritional management is often more successful and more appropriate than treatment with medication. Some therapists specializing in eating disorders may have expertise in treating pica.
The prognosis for individuals with pica varies greatly, according to the type and amount of substance ingested, the extent of presenting side effects, and the success of treatment. Many of the side effects and complications of pica can be reversed once the behavior is stopped, while other complications, including infection and bowel perforation, pose significant health threats and if not successfully treated may result in death.
When seen in children, pica behavior tends to lessen with age. However, individuals with a history of pica are more likely to experience it again. Counseling and nutritional education can reduce the risk of recurrence.
There are no known methods of preventing pica. However, once pica is known or suspected, measures can be taken to reduce further ingestion of non-food substances. Removing the particular substance from readily accessible areas can be helpful. Close observation of the individual with pica may limit inappropriate eating behaviors.
Pica may be a symptom of an underlying nutritional deficiency. Correcting the deficiency usually stops the pica.
Parents should monitor the food and other substances that their children eat. Repeated ingestion of non-food substances may be cause for concern. An evaluation by a pediatrician is recommended in such circumstances. Parents should be especially careful of children who eat paint chips, because this can cause lead poisoning if the paint is from an older home in which lead paint was used.
Amylophagia—The compulsive eating of purified starch, typically cornstarch or laundry starch.
Geophagia—The compulsive eating of earth substances, including sand, soil, and clay.
Pagophagia—The compulsive eating of ice.
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L. Fleming Fallon, Jr., MD, DrPH