Differential Diagnosis for Pruritic Pediatric Rash with Fever

Single Most Likely Diagnosis

• Viral Exanthem: This is the most common cause of a pruritic rash with fever in pediatric patients. Viral exanthems, such as those caused by enteroviruses, adenoviruses, and parvovirus B19, often present with a rash and fever, and can be pruritic.

Other Likely Diagnoses

• Allergic Contact Dermatitis: This condition occurs when the skin comes into contact with an allergen, causing a pruritic rash. In pediatric patients, common allergens include nickel, fragrances, and latex.
• Atopic Dermatitis (Eczema): A chronic skin condition characterized by dry, itchy skin, and is often accompanied by fever in acute exacerbations.
• Insect Bite Reactions: Reactions to insect bites can cause pruritic rashes and may be accompanied by fever, especially if there is a secondary infection.
• Kawasaki Disease: An acute febrile illness that can present with a rash, although it is not typically pruritic. However, it's essential to consider due to its potential for serious cardiac complications.

Do Not Miss Diagnoses

• Meningococcemia: A life-threatening infection caused by Neisseria meningitidis, which can present with a rash (often petechial or purpuric) and fever. Although the rash is not typically pruritic, the severity of the condition warrants its inclusion in this category.
• Rocky Mountain Spotted Fever (RMSF): A tick-borne illness caused by Rickettsia rickettsii, characterized by fever, headache, and a rash. The rash can be pruritic in some cases, and RMSF is a potentially fatal disease if not treated promptly.
• Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN): A severe skin condition usually caused by medications or infections, characterized by a rash, fever, and skin necrosis. While not typically pruritic, the condition's severity and potential for mortality make it crucial not to miss.

Rare Diagnoses

• Pityriasis Rosea: A skin condition characterized by a pruritic rash, often preceded by a herald patch. It is relatively rare and its cause is unknown, but it can be accompanied by fever in some cases.
• Scarlet Fever: Caused by Group A beta-hemolytic streptococci, this condition presents with a rash, fever, and other systemic symptoms. The rash is typically not pruritic but can be considered in the differential diagnosis due to its distinctive appearance and potential for complications if not treated.