Can be due to mineral deficiency or toxicity. But can become habitual, in which case motives/consequences should be explored – attention? Escape? Sensory feedback?

Usually iron deficiency, but potentially calcium, zinc. Beware vitamin deficiencies esp C. 

Lead exposure can come from toys sourced from outside EU.
Houses in area built before 1950? Water companies generally screen for this, houses are occasionally notified of a hazard. But lead poisoning can also be a consequence of pica.

Complications are rare but potential for bezoar formation, gastrointestinal side effects. Toxocariasis if faeces is ingested.

Management

• Ignore or avoid negative attention (eye contact, facial expression, speech)
• Other oral stimulation eg. chew wristbands
• Reward keeping hands in pockets?
• Teach edible vs. Non-edible
• Alternative communications methods
• Provide similar smells, textures, colours to play with or eat