Feeding disorder
A feeding disorder, in infancy or early childhood, is a child's refusal to eat certain food groups, textures, solids or liquids for a period of at least one month, which causes the child to not gain enough weight, grow naturally or cause any developmental delays. Feeding disorders resemble failure to thrive, except that at times in feeding disorder there is no medical or physiological condition that can explain the very small amount of food the children consume or their lack of growth. Some of the times, a previous medical condition that has been resolved is causing the issue. Types
Feeding disorder has been divided into six further sub-types:

 Feeding disorder of state regulation
 Feeding disorder of reciprocity (neglect)
 Infantile anorexia
 Sensory food aversion
 Feeding disorder associated with concurrent medical condition
 Post-traumatic feeding disorder

Symptoms and signs 
Children attempting to swallow different food textures often vomit, gag, or choke while eating. At feeding times they may react negatively to attempts to feed them, and refuse to eat. Other symptoms include head turns, crying, difficulty in chewing or vomiting and spitting whilst eating. Many children may have feeding difficulties and may be picky eaters, but most of them still have a fairly healthy diet. Children with a feeding disorder however, will completely abandon some of the food groups, textures, or liquids that are necessary for human growth and development 

Children with this disorder can develop much more slowly because of their lack of nutritional intake. In severe cases the child seems to feel socially isolated because of the lack of social activities involving foods. Associated problems
A few of the medical and psychological conditions that have been known to be associated with this disorder include:
Gastrointestinal motility disorders 
Oral-motor dysfunction 
Failure to thrive 
Prematurity 
Food allergies
Sensory problems
Reflux
Feeding tube placement

A child that is suffering from malnutrition can have permanently stunted mental and physical development. Getting treatment early is essential and can prevent many of the complications. They can also develop further eating disorders later in life such as anorexia nervosa, or they could become a limited eater—though they could still be a healthy child they may become a picky eater. Diagnosis
A barium swallow test is often performed, where the child is given a liquid or food with barium in it. This allows the consulting medical practitioners to trace the swallow-function on an X-ray or other investigative system such as a CAT scan. An endoscopic assignment test can also be performed, where an endoscope is used to view the oesophagus and throat on a screen. It can also allow viewing of how the patient will react during feeding. Treatments
There is no quick cure, and treatment will be based on what problems may be causing the feeding disorder. Depending on the condition, the following steps can be taken: increasing the number of foods that are accepted, increasing the amount of calories and the amount of fluids; checks for vitamin or mineral deficiencies; finding out what the illnesses or psychosocial problems are. To accomplish these goals patients may have to be hospitalized for extensive periods of time. Treatment involves professionals from multiple fields of study including, but not limited to; behavior analysts (Behavioral interventions), occupational and speech therapist who specialize in feeding disorders, dietitians, psychologists and physicians. To obtain the best results, treatment should include a behavior modification plan under the guidance of multiple professionals. If the child has oral motor difficulties related to the feeding disorder a pediatric occupational or speech therapist who is trained in feeding disorders and oral motor function should help develop a plan. Epidemiology
Some 25% to 40% of young children are reported to have feeding problems—mainly colic, vomiting, slow feeding, and refusal to eat. It has been reported that up to 80% of infants with developmental handicaps also demonstrate feeding problems while 1 to 2% of infants aged less than one year show severe food refusal and poor growth. Among infants born prematurely, 40% to 70% experience some form of feeding problem. See also
Avoidant/restrictive food intake disorder

References 

Malnutrition
Eating disorders
Infant feeding