What are the typical symptoms of foot and mouth disease in adults?

Clinical Presentation of Hand, Foot, and Mouth Disease in Adults

Hand, foot, and mouth disease in adults presents with fever, oral ulcers, and a characteristic maculopapular or vesicular rash on the palms, soles, and often the buttocks, though the presentation is frequently more atypical and severe compared to children. 1, 2, 3

Classic Clinical Features

Constitutional Symptoms

• Fever is the most common presenting symptom, typically appearing at disease onset 1, 3
• Sore throat frequently accompanies the fever and precedes the development of oral lesions 3
• The febrile illness is usually brief, lasting less than one week in uncomplicated cases 4

Oral Manifestations

• Painful oral ulcers develop in the mouth, affecting the buccal mucosa, tongue, and palate 1, 4
• These ulcers can significantly impact eating and drinking, requiring specific management strategies 1
• The oral lesions typically appear early in the disease course and may be the most symptomatic feature in adults 3

Skin Manifestations

• Maculopapular or vesicular rash characteristically affects the palms and soles 1, 2, 4
• The buttocks are commonly involved, which is part of the typical distribution pattern 4
• Lesions may also appear on the dorsal surfaces of hands and feet, not just palmar-plantar areas 1

Atypical Presentations in Adults

Coxsackievirus A6 has emerged as a major cause of atypical HFMD presentations in adults, with more widespread and severe skin involvement than classic disease. 1, 2, 5

Atypical Skin Patterns

• Widespread exanthema extending beyond the classic hand-foot-mouth distribution, involving the legs, trunk, and extremities 1, 2, 5
• Vesiculobullous eruptions that may be more prominent and extensive than in children 2, 5
• Perioral zone involvement, which is uncommon in classic HFMD 2
• The rash may mimic other serious conditions including eczema herpeticum, varicella, disseminated zoster, or erythema multiforme major 5

Important Distinguishing Features

• Immunocompetent adults can develop HFMD through familial transmission from infected children, contrary to the common belief that it only affects immunocompromised adults 2
• The disease remains self-limiting in most adult cases with complete recovery expected 2, 3

Severe Complications to Monitor

While rare, adults can develop serious complications that require vigilance:

• Neurological complications including encephalitis, meningitis, acute flaccid paralysis, and acute flaccid myelitis, particularly with Enterovirus 71 1, 6
• Cardiopulmonary complications such as myocarditis and pulmonary edema have been reported 2
• These severe manifestations occur more commonly with EV-A71 infections, especially in Asian outbreaks 1, 6

Late Sequelae

• Beau's lines (deep transverse nail grooves) may appear approximately 1-2 months after fever onset as a delayed manifestation 1
• Periungual desquamation typically begins 2-3 weeks after disease onset 1
• These late findings represent resolved disease rather than active infection and do not require specific treatment 1

Critical Differential Diagnoses

You must distinguish HFMD from herpes simplex virus infection, as HSV has available antiviral treatment whereas HFMD does not. 1

Other important differentials to consider:

• Drug hypersensitivity reactions (can present with palmar-plantar rash) 1
• Kawasaki disease (presents with diffuse erythema rather than vesicular lesions) 1
• In atypical presentations with palmar-plantar involvement: syphilis, meningococcemia, and Rocky Mountain spotted fever 1

Diagnostic Approach

• Clinical diagnosis is typically sufficient in classic presentations with the characteristic triad of fever, oral ulcers, and hand-foot rash 3, 4
• RT-PCR testing of vesicle fluid (highest viral load), respiratory samples, or stool specimens confirms the diagnosis when needed 1
• Laboratory confirmation is particularly valuable in atypical presentations or outbreak settings 1, 5