Pica

An eating disorder less often encountered by oral health professionals is pica. This disorder is typically defined as the compulsive eating of non-nutritive substances for a period of at least one month at an age for which this behavior is developmentally inappropriate (after age 18 to 24 months), and not a culturally sanctioned practice.37,38

The term pica comes from the Latin word meaning magpie and reflects this bird’s peculiar eating habits; they show an indiscriminate preference for food and non-food substances. Non-food substances ingested by individuals with pica appear in Table V.

The prevalence of pica in the United States is unknown. This eating disorder is frequently unrecognized and underreported. Pica is frequently observed in children, individuals with developmental disabilities, and pregnant women. Children with mental retardation and autism are affected more frequently, and the severity of pica increases with increasing severity of mental retardation.37

Pica behavior is also known to occur ritualistically in some cultures. Geophagia (clay ingestion) is the most common form of pica, occurring in tribe-oriented societies as well as in people living in the tropics. It was a common act during the 1800s in the southern United States, primarily among slaves. Pica has been practiced as part of religious ceremonies, magical beliefs, and attempts at healing.39

The etiology of pica remains unknown; however, numerous hypotheses have been proposed to explain this unusual phenomenon. Cultural, socioeconomic, organic and psychodynamic factors have been cited as causes. Nutritional deficiencies of minerals, iron, and zinc appear to be a common theory concerning the etiology of pica. Sayetta reported studies of individuals with pica with low iron and zinc levels whose pica behavior diminished when iron or zinc supplements were given.40 However, empirical evidence remains unconfirmed. Sensory and physiologic theories focus on the finding that individuals with pica claim to enjoy the taste, texture, or smell of the item they are eating. Psychosocial theories related to pica have examined the association of family stress such as maternal deprivation, parental separation, parental neglect, and child abuse involving pica. Investigations have examined an underlying biochemical disorder, like a diminished dopaminergic neurotransmission, but correlations have not been identified empirically.37,38
Others have proposed that pica is part of the obsessive-compulsive disorder (OCD) spectrum of diseases, in which practicing a ritualistic behavior leads to relief of tension and anxiety.41-43 Risk factors for pica include parental/child psychopathology, family disorganization, environmental deprivation, pregnancy, epilepsy, brain damage, mental retardation, and developmental disorders.37

Manifestations of pica vary and include inherent toxicity, obstruction, excessive caloric intake, nutritional deprivation, infection, and injury. Of concern is the toxicity associated with ingestion of lead or other heavy metals. Physical manifestations of lead poisoning can include neurologic (e.g., irritability, lethargy, incoordination, headache, cranial nerve paralysis, seizures, coma, and death) and gastrointestinal (e.g., constipation, abdominal pain, colic, vomiting, anorexia, diarrhea) symptoms. Gastrointestinal symptoms, such as mechanical bowel problems, ulcerations, perforations, and obstructions may occur due to ingesting substances that are undigestible, such as hair eating. Infections and parasitic infestations are also a concern. Toxocariasis is the most common soil-borne parasitic infection associated with pica and can lead to fever, hepatomegaly, malaise, cough, myocarditis, encephalitis, retinal lesions, and loss of vision.

Diagnosis of pica can be difficult and frequently depends on selfreporting. Accurate diagnosis is often hindered by reluctance to report the practice as well as the secretiveness on the part of individuals with pica and their families. In suspected cases, laboratory studies that may be performed include a complete blood count, iron level, ferritin level, lead level, electrolytes, and liver function studies. Abdominal radiographs, upper and lower GI barium examinations, and an upper GI endoscopy may be needed to evaluate for intestinal obstructions, bezoar formation, or parasites. Stool cultures can be used to rule out ova and parasites. Parents should be interviewed about the dietary habits and pica behaviors of children. Furthermore, individuals with pica symptoms may be assessed for OCD and impulse control disorders through psychological evaluations.