Differential Diagnosis for Rash after Fevers in Children
Single Most Likely Diagnosis
- Roseola infantum (Exanthem subitum): This is a common illness in children characterized by a high fever followed by a rash. The fever typically lasts for 3-5 days and then resolves, followed by the appearance of a rash. The rash is usually pink, blanching, and maculopapular, and it fades within a few days.
Other Likely Diagnoses
- Viral exanthems (e.g., measles, rubella, erythema infectiosum): These are common viral infections that can cause fever and rash in children. Each has distinct features, such as the characteristic rash distribution and accompanying symptoms.
- Scarlet fever: Caused by Group A beta-hemolytic streptococci, it presents with a sandpapery rash, fever, and other symptoms like a strawberry tongue.
- Kawasaki disease: An acute febrile illness of childhood that presents with fever, rash, conjunctivitis, cervical lymphadenopathy, and changes in the lips and oral cavity. It's an important diagnosis to consider due to its potential for cardiac complications.
Do Not Miss Diagnoses
- Meningococcemia: A severe infection caused by Neisseria meningitidis, which can present with fever and a rash. The rash can be petechial or purpuric and is a medical emergency due to the risk of sepsis and meningitis.
- Rocky Mountain spotted fever: A tick-borne illness caused by Rickettsia rickettsii, characterized by fever, headache, and a rash that can be petechial. It's critical to diagnose promptly due to its high mortality rate if untreated.
- Toxic shock syndrome: A condition caused by bacterial toxins, often presenting with fever, rash, and hypotension. It requires immediate medical attention due to its potential for severe complications.
Rare Diagnoses
- Juvenile idiopathic arthritis (JIA) with systemic onset: This form of JIA can present with fever, rash, and arthritis. The rash is often evanescent and can be tricky to diagnose.
- Infectious mononucleosis: Caused by Epstein-Barr virus, it can occasionally present with a rash, especially if the patient is taking ampicillin or other penicillins.
- Enteroviral infections (e.g., hand, foot, and mouth disease): While common, certain types of enteroviral infections can cause more severe symptoms, including fever and rash, and are worth considering in the differential diagnosis.