Differential Diagnosis for Itchy Rash in a 6-year-old

Single most likely diagnosis

• Atopic Dermatitis (Eczema): This is the most common skin condition in children, characterized by itchy, inflamed skin. The age of the patient and the symptom of an itchy rash make atopic dermatitis a highly probable diagnosis.

Other Likely diagnoses

• Contact Dermatitis: This condition occurs when the skin comes into contact with an allergen or irritant, leading to an itchy rash. Common allergens include poison ivy, oak, or sumac, as well as certain metals or chemicals.
• Insect Bites: Insect bites from mosquitoes, fleas, or bed bugs can cause itchy rashes in children.
• Scabies: A contagious skin infestation caused by the mite Sarcoptes scabiei, leading to intense itching and a pimple-like rash.
• Keratosis Pilaris: A harmless condition that causes dry, rough patches on the skin, often accompanied by itching.

Do Not Miss (ddxs that may not be likely, but would be deadly if missed)

• Meningococcemia: Although rare, this condition can present with a rash and is life-threatening if not promptly treated. The rash associated with meningococcemia is typically non-blanching (does not fade when pressed).
• Stevens-Johnson Syndrome: A severe skin and mucous membrane disorder, usually a reaction to medication or infection, which can be life-threatening.

Rare diagnoses

• Pityriasis Rosea: A rare skin condition characterized by a rash that starts with a single, large spot (herald patch), followed by smaller spots.
• Tinea Corporis (Ringworm): A fungal infection of the skin that can cause a ring-shaped, itchy rash.
• Urticaria: Hives can cause itchy rashes, but they are usually transient and may be accompanied by other symptoms like swelling.
• Bullous Pemphigoid: A rare autoimmune disease that causes blistering of the skin, which can be itchy.