Definition and epidemiology
Pica is the persistent eating of substances with no nutritional value (dirt, chalk, ice, hair, paper, paint chips, soap) for at least one month, in a manner that is not developmentally normal and not part of a culturally sanctioned practice.
- Mouthing non-food items is normal in infants under 18-24 months; pica is diagnosed only when it persists beyond this age or is severe enough to cause harm.
- Prevalence estimates vary widely (roughly 10-30% in young children, higher in institutionalized populations) because of inconsistent reporting and overlap with normal exploratory behavior.
- Common at-risk groups: children ages 2-6, pregnant women (particularly in regions with high rates of iron-deficiency anemia), and individuals with intellectual disability, autism spectrum disorder, or schizophrenia.
- Can occur as an isolated diagnosis or alongside another psychiatric or developmental condition; when it occurs with another disorder, it must be severe enough to warrant separate clinical attention.
- Pica = persistent ingestion of non-food substances for ≥1 month, inappropriate for developmental age.
- Strongly linked to iron deficiency anemia; always check ferritin/iron studies.
- Pagophagia (ice) and geophagia (dirt/clay) are the classic presentations tested on exams.
- Common in pregnancy, young children, intellectual disability, and autism spectrum disorder.
- Diagnosis requires exclusion of normal infant mouthing (not diagnosed before ~age 2) and culturally sanctioned practices.
- Clay ingestion can bind iron and zinc, worsening the deficiency that may have triggered the behavior.
- Check lead level if paint chips or old-building soil exposure is suspected.
- First-line management: correct deficiency + behavioral therapy; no specific drug treats pica itself.
Etiology and risk factors
The cause is multifactorial and not fully understood. Leading explanatory models include nutritional deficiency, physiologic/sensory drive, cultural practice, and psychological or developmental factors.
- Iron deficiency anemia is the most consistently reported association; craving ice or dirt may reflect a (debated) physiologic attempt to correct deficiency, or deficiency may itself impair taste/smell regulation leading to abnormal cravings.
- Zinc deficiency has also been linked, especially with geophagia.
- Pregnancy increases risk, partly due to increased iron demand and partly through cultural practices (geophagia is traditional in some communities).
- Developmental and psychiatric conditions: intellectual disability, autism spectrum disorder, schizophrenia, and obsessive-compulsive disorder increase risk.
- Psychosocial stressors: neglect, poverty, lack of parental supervision, and malnutrition are commonly reported contributing factors in children.
- Family and cultural patterns: in some cultures, eating clay or starch is a learned, socially accepted practice (distinguish from pathological pica by context and consequence).
Pathophysiology
There is no single unifying mechanism; several hypotheses are proposed and may coexist.
- Nutritional hypothesis: deficiency of iron or zinc may alter taste perception or trigger compensatory ingestive behavior, though cause-and-effect is not firmly established (deficiency may be a consequence of pica rather than, or in addition to, its cause, because ingested substances can impair absorption of nutrients).
- Sensory/behavioral hypothesis: in children with autism or intellectual disability, pica may represent a form of sensory-seeking or self-stimulatory behavior reinforced by oral sensation.
- Learned/operant model: in some cases pica is maintained by automatic reinforcement (the sensory experience itself) or social reinforcement (attention from caregivers).
- Toxic/mechanical consequences: ingested substances can bind minerals (e.g., clay binding iron and zinc, worsening deficiency), introduce toxins (lead-containing paint), or cause mechanical injury (bezoars, intestinal obstruction, dental damage).
Clinical features
Presentation ranges from an incidental finding on history to a medical emergency from a complication.
- Reported or observed repeated ingestion of a specific non-food substance (most common: ice, dirt/clay, chalk, paper, hair, soap, paint).
- Often minimized or hidden by the patient, especially adults and adolescents, due to embarrassment.
- May be discovered through a parent's report, incidental abdominal imaging, unexplained anemia, elevated lead levels, or gastrointestinal symptoms.
- Associated findings depend on the substance: constipation or bowel obstruction (fiber-rich non-food items, hair forming trichobezoars), abdominal pain, dental wear or breakage (ice, hard substances), lead poisoning (paint chips, soil near old buildings), and parasitic infection (soil contaminated with helminth eggs).
- Screen specifically in pregnant patients with unusual cravings, in children with developmental delay, and in anyone with iron-deficiency anemia resistant to standard explanation.
Diagnosis
Diagnosis is clinical, based on history, and requires exclusion of developmentally normal mouthing behavior and culturally sanctioned practices.
DSM-5-TR criteria (used for ICD-10 classification purposes)
- Persistent eating of non-nutritive, non-food substances for at least 1 month.
- Behavior is inappropriate to developmental level (not diagnosed before approximately age 2).
- Not part of a culturally supported or socially normative practice.
- If occurring in the context of another mental disorder or medical condition, it must be severe enough to warrant independent clinical attention.
Workup
- Detailed history: substance ingested, frequency, duration, context (pregnancy, stress, developmental history).
- CBC and iron studies (ferritin, serum iron, TIBC) to evaluate for iron deficiency anemia.
- Zinc level if clinically indicated.
- Blood lead level if paint, soil, or old housing exposure is suspected.
- Abdominal imaging (X-ray/CT) if obstruction or bezoar is suspected.
- Stool studies for ova and parasites if soil/clay ingestion with GI symptoms.
- Dental evaluation if chronic ice or hard-substance chewing.
Differential diagnosis
| Condition | Distinguishing feature |
|---|---|
| Normal infant mouthing behavior | Developmentally appropriate, resolves by ~2 years |
| Avoidant/restrictive food intake disorder (ARFID) | Food avoidance/restriction, not ingestion of non-food items |
| Rumination disorder | Repeated regurgitation and re-chewing of food, not ingestion of non-food substances |
| Anorexia nervosa / bulimia nervosa | Disturbance centers on body image and food restriction/purging, not non-food ingestion |
| Culturally sanctioned geophagia | Socially accepted, non-pathological, no functional impairment |
| Autism spectrum disorder with mouthing behavior | Pica may be a separate co-diagnosis if criteria met; evaluate independently |
Management
Management is individualized, combining medical correction of deficiencies, behavioral intervention, and treatment of underlying conditions. There is no single approved pharmacologic treatment for pica itself.
- Correct nutritional deficiencies: iron or zinc supplementation when deficiency is confirmed; craving behavior often (though not always) improves with correction.
- Behavioral therapy: first-line for children and individuals with intellectual disability or autism; approaches include differential reinforcement of alternative behavior, response interruption/redirection, and environmental modification to limit access to non-food items.
- Address underlying psychiatric or developmental disorders: manage comorbid autism, intellectual disability, OCD, or schizophrenia per standard guidelines for those conditions.
- Address psychosocial stressors: improve supervision, nutrition, and caregiver education, especially in children with neglect or food insecurity.
- Monitor and treat complications: deworming if parasitic infection confirmed, chelation therapy if significant lead toxicity, surgical or endoscopic removal of bezoars causing obstruction.
- Patient and family education: explain risks of specific substances (lead, infection, choking, mechanical obstruction) and the importance of follow-up.
- Guideline consensus (DSM-5-TR framework, supported by pediatric and psychiatric society guidance) emphasizes a stepwise approach: rule out and treat deficiency first, then behavioral intervention, with pharmacologic agents reserved for treating comorbid conditions rather than pica itself.
Complications and prognosis
Prognosis is generally favorable in young children, who often outgrow the behavior, but can be more persistent in intellectual disability, autism, or chronic psychosocial adversity.
- Gastrointestinal: bezoars, intestinal obstruction or perforation, constipation, parasitic infection (soil/clay).
- Toxicologic: lead poisoning (paint, contaminated soil), other heavy metal exposure.
- Nutritional: worsening of iron/zinc deficiency due to impaired absorption from ingested substances (e.g., clay binding minerals), paradoxically perpetuating the cycle.
- Dental and oral: enamel wear, tooth fracture (chronic ice chewing).
- Obstetric: in pregnancy, pica has been associated with maternal anemia and, in some studies, adverse birth outcomes, though data quality varies.
- With correction of deficiency and appropriate behavioral support, many cases resolve, particularly in childhood; relapse can occur with recurrence of deficiency or stress.
PICA = Persistent Ingestion of Craving-driven, Atypical (non-food) substances — think "iron-deficient PICA patient craving ICE."
Practice questions
1. A 3-year-old girl is brought to clinic because her mother noticed her repeatedly eating dirt from the backyard over the past 3 months. She lives in an older home built in the 1960s. Physical exam is unremarkable. Which laboratory test is most important to obtain next?
2. A 24-year-old woman at 28 weeks gestation reports an intense craving to chew ice several times a day for the past month, which she finds embarrassing but cannot resist. Her hemoglobin is 9.8 g/dL with low ferritin. What is the most appropriate next step in management?
3. A 10-year-old boy with autism spectrum disorder and moderate intellectual disability is noted by his group home staff to frequently eat paper and small pieces of foam. Iron studies and lead level are normal, and he has no GI symptoms. Which intervention is most appropriate as first-line treatment?
Frequently asked questions
What causes pica?
Pica has no single cause; it is most strongly linked to iron and zinc deficiency, and is also associated with pregnancy, intellectual disability, autism spectrum disorder, and psychosocial stressors like neglect or poverty. In some cultures, eating substances like clay is a learned, socially accepted practice rather than a disorder. Often the exact trigger in an individual case cannot be pinpointed.
What are the first signs of pica?
The first sign is usually repeated eating of a specific non-food item such as ice, dirt, chalk, paper, or hair, often noticed by a caregiver or found incidentally. In adults it may first appear as unexplained iron-deficiency anemia, dental damage from chewing ice, or gastrointestinal symptoms. Many people hide the behavior out of embarrassment, so a direct, non-judgmental history is key.
How is pica diagnosed?
Pica is diagnosed clinically using DSM-5-TR criteria: persistent eating of non-nutritive substances for at least one month, inappropriate for developmental level, and not a culturally sanctioned practice. Workup typically includes a detailed history plus CBC, iron studies, and sometimes zinc or lead levels, with imaging if obstruction is suspected. There is no lab test that confirms pica itself; labs are used to find underlying causes and complications.
Is pica curable?
Pica is often temporary, especially in young children, who commonly outgrow it, and in pregnancy, where it frequently resolves after delivery or correction of iron deficiency. In individuals with intellectual disability or autism, it can be more persistent and may require ongoing behavioral management. Treating any underlying deficiency and using behavioral strategies leads to improvement in most cases, though relapse is possible.
Pica vs rumination disorder — what is the difference?
Pica involves eating non-food substances like dirt, chalk, or ice, while rumination disorder involves repeatedly regurgitating previously swallowed food and either re-chewing, re-swallowing, or spitting it out. Both are feeding and eating disorders that can occur in children or adults with developmental disabilities, but they involve entirely different behaviors and are diagnosed using separate DSM-5-TR criteria.
Key drugs
Related conditions and differentials
Sources and further reading
StatPearls (NCBI Bookshelf)MedlinePlusWHO ICD-10: F50.8
Educational content for medical students, prepared by the WhiteCoat Pro editorial team with AI assistance; every page is reviewed by a second AI model for factual errors. It is not medical advice and does not replace the product label, local guidelines or a clinician.