Pica: An age-old eating disorder that’s often missed

CASE › A 6-year-old African girl, developing and growing appropriately for age, was brought to our clinic by her father with the chief complaint of “eating the textbooks at school.” The child had eaten paper for years, the father said; he never thought it unusual until her teacher brought it to his attention. The father reported that his daughter had met all developmental milestones and was up to date with her immunizations. When asked why she ate paper, the child responded, “I don’t know.”

The child was diagnosed with pica and, because we were concerned that she was eating other nonnutritive foods, we ordered hematologic studies. Her lead level (2 mcg/dL) was within the normal range; her hemoglobin/hematocrit was 10.4 g/dL/32.3%. Iron therapy was started. At follow-up 4 weeks later, the child’s paper-eating behavior had resolved.

The word pica comes from the Latin word for magpie, a bird with a reputation for eating practically anything. The Diagnostic and Statistical Manual of Mental Disorders, 5th edition, defines pica as persistent eating of nonnutritive substances for at least 1 month that is inappropriate to developmental level and not part of a culturally supported or socially normative practice.¹

Case reports on paper pica are few, but numerous reports describe other forms of the behavior, including eating ice; dirt, soil, and clay; starch; burnt matches; cardboard; hair; laundry detergent; chalk; soap; firecrackers; and metal artifacts such as coins.^2-16

Pica has been described in the literature as “underreported” and “unrecognized.” Its true prevalence is difficult to assess because most people don’t report it and the methodology of data collection varies among populations, as does the definition of pica. According to some estimates, more than 50% of children ages 18 to 36 months seek and ingest nonfood items. The practice reportedly decreases as a child ages, but an estimated 10% of children older than 12 years may engage in it.¹⁷

Pica has been reported since antiquity. Many medical and anthropological studies refer to the practice of geophagia, or dirt eating, which is prevalent in Africa and among small children and women, particularly women who are native to the southern United States, African-American, or pregnant.^5-10,18,19

Pica often occurs in people with developmental disabilities such as autism and is considered a psychiatric condition in that context.^{3,11,15,20-31} However, because many forms of pica, especially geophagia, aren’t associated with mental health issues, researchers disagree about whether to consider it an abnormal behavior. A 2000 workshop on pica organized by the Agency for Toxic Substances and Disease Registry concluded that geophagia is not an abnormal behavior.¹⁷ One of the most compelling arguments for this view is that dirt eating is far too common around the world to be considered abnormal, and dirt is held in some cultures to have therapeutic powers.^7,13,24

Adverse outcomes linked to pica

Pica is associated with adverse outcomes, however. A study by the Agency for Healthcare Research and Quality found that despite an overall decline in hospitalizations for eating disorders, hospitalizations for pica have risen.²⁵ From 1999 to 2009, pica-related hospitalizations jumped 93%, although the overall number of patients hospitalized for the condition remains small (964 in 1999 to 2000, 1862 in 2008-2009).

Adverse effects of pica include potassium abnormalities and GI conditions ranging from abdominal pain to perforation, blockage, and colon ischemia.Documented adverse effects of pica include potassium abnormalities and gastrointestinal conditions ranging from irritation and abdominal pain to perforation, blockage, and colon ischemia.^3,11,26-29 Reported bidirectional effects (which both result from and contribute to pica) include iron deficiency, parasitic infections, and heavy metal exposure—particularly lead, mercury, and arsenic.^{4,6,9,20,30-38}

Diagnosis: Focus on history and selective testing

Pica is a clinical diagnosis, confirmed by the patient’s history, not any single laboratory test. Providers should ask about pica behavior or unusual cravings in certain high-risk groups: pregnant women, particularly women from the southern United States, immigrants or refugees, and children and adults with autism or other developmental disabilities.^18,22

Testing should be based on the type of pica behavior. Because various forms of pica are commonly associated with iron-deficiency anemia, obtain serum hemoglobin and hematocrit levels along with iron levels if necessary in patients who report cravings for unusual substances. Pica in pregnancy is a sign of iron deficiency, but it also may signal iron deficiency in patients who aren’t pregnant. In one study of 262 nonpregnant adults with iron-deficiency anemia, 45% reported pica behaviors; of these, 87.3% reported eating ice.³⁴