Differential Diagnosis for a Child Not Eating but Active and Alert

• Single Most Likely Diagnosis
  • Picky Eating or Normal Variability in Appetite: Many children go through phases where they are less interested in food due to various reasons such as changes in taste preferences, teething, or simply because they are not hungry at the time of meals. This is often seen in children who are otherwise active, alert, and growing well.
• Other Likely Diagnoses
  • Gastroesophageal Reflux Disease (GERD): Children with GERD may refuse to eat because feeding can exacerbate their reflux symptoms, leading to discomfort or pain.
  • Constipation: Constipation can lead to decreased appetite in children due to discomfort or pain associated with bowel movements.
  • Food Allergies or Intolerances: Allergies or intolerances to certain foods can cause symptoms that make eating unpleasant, such as abdominal pain, diarrhea, or rash.
  • Oral Motor or Sensory Issues: Some children may have difficulties with the physical act of eating due to oral motor problems or sensory issues related to food textures, smells, or tastes.
• Do Not Miss Diagnoses
  • Infections (e.g., Urinary Tract Infections, Ear Infections): Certain infections can cause a decrease in appetite, and while they may not be immediately life-threatening, they require prompt treatment to prevent complications.
  • Diabetes Mellitus: Though less common, new-onset diabetes can present with decreased appetite among other symptoms like increased thirst and urination.
  • Thyroid Disorders: Both hyperthyroidism and hypothyroidism can affect appetite, though other symptoms are typically more prominent.
• Rare Diagnoses
  • Cystic Fibrosis: A genetic disorder that can lead to malabsorption and decreased appetite due to gastrointestinal complications.
  • Celiac Disease: An autoimmune reaction to gluten that can cause malabsorption, leading to decreased appetite among other symptoms.
  • Chronic Diseases (e.g., Congenital Heart Disease, Renal Disease): Certain chronic conditions can affect a child's appetite due to the disease process itself or the side effects of treatment.

Each of these diagnoses should be considered in the context of the child's overall clinical presentation, including physical examination findings, growth parameters, and any additional symptoms that may be present. A thorough history and physical examination, along with selective use of diagnostic tests, can help narrow down the differential diagnosis and guide appropriate management.