Differential Diagnosis of Maculopapular Rash in Children Under 5 Years Old
Single Most Likely Diagnosis
- Viral Exanthem: This is the most common cause of maculopapular rash in children, often associated with fever. Viruses such as enterovirus, adenovirus, and respiratory syncytial virus (RSV) are frequent culprits. The rash typically appears after the onset of fever and other systemic symptoms.
Other Likely Diagnoses
- Roseola (Exanthem Subitum): Caused by human herpesvirus 6 (HHV-6) or 7 (HHV-7), it presents with high fever followed by a maculopapular rash once the fever resolves.
- Measles: Although vaccination has reduced its incidence, measles remains a consideration, especially in unvaccinated children. It is characterized by a maculopapular rash, fever, cough, runny nose, and conjunctivitis.
- Rubella (German Measles): Another vaccine-preventable disease, rubella presents with a maculopapular rash, fever, and lymphadenopathy.
- Erythema Infectiosum (Fifth Disease): Caused by parvovirus B19, it is known for its "slapped cheek" appearance and maculopapular rash on the body, often accompanied by mild fever.
Do Not Miss Diagnoses
- Meningococcemia: A life-threatening condition caused by Neisseria meningitidis, which can present with a petechial or purpuric rash (that may initially appear maculopapular), fever, and signs of sepsis. Prompt recognition and treatment are crucial.
- Kawasaki Disease: An acute febrile illness that can cause a maculopapular rash, along with other symptoms like conjunctivitis, cervical lymphadenopathy, and changes to the lips and oral cavity. It requires early diagnosis to prevent cardiac complications.
- Staphylococcal Scalded Skin Syndrome (SSSS): Caused by staphylococcal toxins, SSSS presents with fever, rash, and skin exfoliation. It is more common in infants and young children.
Rare Diagnoses
- Juvenile Idiopathic Arthritis (JIA): Some forms of JIA can present with a maculopapular rash, fever, and joint inflammation.
- Infectious Mononucleosis: Caused by Epstein-Barr virus (EBV), it can occasionally present with a maculopapular rash, especially if the child is taking ampicillin.
- Lyme Disease: In endemic areas, Lyme disease can cause a distinctive "bull's-eye" rash (erythema migrans), fever, and other systemic symptoms.
- Rickettsial Infections: Such as Rocky Mountain spotted fever, which can present with a maculopapular rash, fever, and headache, although it is more common in older children and adults.