Differential Diagnosis for 4-year-old Female with Skin Irritation

• Single most likely diagnosis
  • Atopic dermatitis (eczema): Given the patient's history of allergies and the location of skin irritation on the bilateral shoulders and posterior knees, atopic dermatitis is a strong consideration. The use of Flonase for chronic rhinorrhea also supports an atopic predisposition.
• Other Likely diagnoses
  • Contact dermatitis: This could be a possibility if the child has come into contact with an allergen or irritant that has caused the skin reaction on the shoulders and knees.
  • Seborrheic dermatitis: Although less common in this age group, seborrheic dermatitis can cause skin irritation and may be considered, especially if the distribution of the rash is more typical for this condition.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Juvenile idiopathic arthritis (JIA): Although skin irritation is not the primary symptom, some forms of JIA can present with skin manifestations, and missing this diagnosis could lead to significant morbidity.
  • Infection (e.g., impetigo, cellulitis): Bacterial infections can cause skin irritation and must be considered to prevent serious complications.
• Rare diagnoses
  • Psoriasis: Although rare in young children, psoriasis can present with skin plaques and should be considered if the clinical presentation is atypical for more common conditions.
  • Cutaneous lymphoma: Extremely rare in children, but any persistent or unusual skin lesion warrants consideration of this diagnosis to ensure early detection and treatment.