What are the clinical manifestations of hand, foot, and mouth disease (HFMD) in adults?

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

Hand, foot, and mouth disease (HFMD) in adults typically presents with fever, sore throat, and a characteristic maculopapular rash on the hands, feet, and oral cavity, though the presentation may be more extensive or atypical compared to children.

Clinical Features

Primary Symptoms

• Fever: Often the initial symptom, typically 39°C or higher 1
• Sore throat: Common presenting complaint in adults 2
• Oral lesions:
  • Painful ulcers and vesicles primarily affecting the tongue, buccal mucosa, and palate
  • Usually the first clinical manifestation 3
  • May cause difficulty eating or drinking

Cutaneous Manifestations

• Distribution: Classic triad involves:
  1. Hands (particularly palms)
  2. Feet (particularly soles)
  3. Oral cavity
• Morphology:
  • Begins as erythematous macules that evolve into papules and vesicles
  • Vesicles may rupture leaving shallow ulcers
  • Lesions typically 3-7mm in diameter
• Additional sites in adults may include:
  • Buttocks
  • Genital area
  • More extensive truncal involvement 4

Atypical Presentations in Adults

Adults may present with more extensive or unusual manifestations:

• Vesicobullous and erosive eruptions
• Periorificial lesions
• Petechial or purpuric eruptions
• Eczema coxsackium (lesions localizing to areas of pre-existing dermatitis) 4

Disease Course and Complications

Timeline

• Incubation period: 3-6 days
• Fever duration: 1-4 days
• Rash evolution: Appears within 1-2 days of fever onset
• Total illness duration: Typically self-limited, resolving within 7-10 days 5

Late Complications

• Nail changes:
  • Nail dystrophy (Beau's lines)
  • Onychomadesis (nail shedding) occurring 3-8 weeks after initial infection 1, 4
• Palmoplantar desquamation: May occur during recovery phase 4

Diagnostic Considerations

Clinical Diagnosis

Diagnosis is primarily clinical, based on:

• Characteristic distribution of lesions
• Presence of fever
• Typical progression of symptoms

Laboratory Testing

• Generally not required for typical cases
• Normal blood tests are common 2
• Viral PCR testing may be performed in atypical or severe cases

Differential Diagnosis

Consider other conditions with similar presentations:

• Herpes simplex virus infection
• Herpangina (primarily posterior oropharyngeal lesions)
• Erythema multiforme
• Recurrent aphthous stomatitis
• Varicella (chickenpox)
• Petechial rashes (consider meningococcemia if accompanied by high fever and systemic toxicity) 6, 3

Management

Treatment Approach

• Supportive care is the mainstay of treatment:
  • Adequate hydration
  • Pain control with acetaminophen or NSAIDs
  • Topical oral anesthetics for painful mouth ulcers
• No specific antiviral therapy is indicated for immunocompetent adults

Patient Education

• Reassurance about the self-limiting nature of the disease 2
• Infection control measures to prevent transmission:
  • Hand hygiene
  • Avoiding close contact during the acute phase
  • Cleaning contaminated surfaces

Key Clinical Pearls

• HFMD in adults is often more severe and extensive than in children
• Adults may be asymptomatic carriers and transmit the infection to children
• Household transmission from children to adults is common
• Consider HFMD in the differential diagnosis of any adult presenting with fever and vesicular rash, especially with palmoplantar and oral involvement
• Recurrence is possible as multiple enterovirus serotypes can cause the disease

HFMD should be recognized promptly to provide appropriate supportive care and prevent unnecessary investigations or treatments for other conditions.