Differential Diagnosis for Urticaria Rash in a Pediatric Patient
Single Most Likely Diagnosis
- Allergic Reaction: The most common cause of urticaria in pediatric patients is an allergic reaction, often triggered by foods, insect bites, or medications. The rash typically starts on the face and spreads to other areas, including the arms.
Other Likely Diagnoses
- Insect Bite or Sting: Insect bites or stings can cause urticaria, especially in children who spend time outdoors. The rash may start at the site of the bite or sting and spread to other areas.
- Viral Infection: Certain viral infections, such as viral exanthems, can cause urticaria in pediatric patients. The rash may be accompanied by other symptoms like fever, cough, and sore throat.
- Food Allergy: Food allergies are common in children, and an allergic reaction to a food can cause urticaria. The most common food allergens include peanuts, tree nuts, milk, eggs, fish, shellfish, wheat, and soy.
Do Not Miss Diagnoses
- Anaphylaxis: Although rare, anaphylaxis is a life-threatening condition that requires immediate attention. It can cause urticaria, as well as other symptoms like difficulty breathing, rapid heartbeat, and a drop in blood pressure.
- Hereditary Angioedema: This rare genetic disorder can cause recurrent episodes of urticaria, as well as swelling of the face, lips, tongue, and airways.
- Mastocytosis: This condition is characterized by an accumulation of mast cells in the skin, which can cause urticaria, as well as other symptoms like flushing, itching, and abdominal pain.
Rare Diagnoses
- Autoimmune Disorders: Certain autoimmune disorders, such as lupus or rheumatoid arthritis, can cause urticaria in pediatric patients. However, these conditions are rare in children and typically require additional symptoms and laboratory tests for diagnosis.
- Urticarial Vasculitis: This rare condition is characterized by inflammation of the blood vessels, which can cause urticaria, as well as other symptoms like fever, fatigue, and joint pain.
- Parasitic Infections: Certain parasitic infections, such as scabies or pediculosis, can cause urticaria in pediatric patients. However, these conditions are relatively rare and typically require additional symptoms and laboratory tests for diagnosis.