Differential Diagnosis for Hand Foot and Mouth Disease

When considering a diagnosis of hand foot and mouth disease (HFMD), it's crucial to differentiate it from other conditions that may present with similar symptoms. Here's a structured approach to the differential diagnosis:

• Single Most Likely Diagnosis

  • Hand Foot and Mouth Disease (HFMD): This is the most likely diagnosis given the question. HFMD is a common viral illness that typically affects infants and children under the age of 5, but can also occur in adults. It is characterized by sores in the mouth and a rash on the hands and feet. The justification for this being the single most likely diagnosis is based on the direct mention of "hand foot and mouth" in the question, suggesting that the symptoms align closely with those of HFMD.

• Other Likely Diagnoses

  • Herpangina: Caused by coxsackieviruses, herpangina presents with painful vesicular lesions on the tonsils and the posterior pharynx, which could be confused with the oral lesions of HFMD.
  • Varicella (Chickenpox): Although it typically presents with a more widespread rash, the initial stages or mild cases could be mistaken for HFMD, especially if the rash is predominantly on the hands and feet.
  • Erythema Multiforme: This skin condition can cause target-like lesions on the skin, which might resemble the rash seen in HFMD, although it usually has a different distribution and is often associated with other symptoms like fever and mucous membrane involvement.

• Do Not Miss Diagnoses

  • Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN): These are severe skin and mucous membrane disorders, usually a reaction to medication or infection. While rare, they are life-threatening and require immediate medical attention. The presence of widespread skin lesions, mucous membrane involvement, and systemic symptoms should prompt consideration of these conditions.
  • Kawasaki Disease: An acute febrile illness of childhood characterized by inflammation in the walls of medium-sized arteries throughout the body, which can lead to serious cardiac complications if not treated promptly. Early symptoms can include rash, fever, and oral changes, which might be confused with HFMD.

• Rare Diagnoses

  • Enteroviral Vesicular Stomatitis with Exanthem: While enteroviruses are the cause of HFMD, certain strains can cause a vesicular stomatitis (mouth blisters) with an exanthem (rash) that might present differently or more severely than typical HFMD.
  • Measles: Although vaccination has made measles rare in many areas, it can present with a rash and fever, and in its early stages, might be confused with HFMD, especially if the characteristic cough, coryza, and conjunctivitis are not prominent.

Each of these diagnoses has distinct features that can help differentiate them from HFMD, emphasizing the importance of a thorough clinical evaluation and, when necessary, diagnostic testing to confirm the diagnosis.