II. Epidemiology

  1. Typically occurs in outbreaks and peaks in some years, with an often several year delay to the next outbreak
  2. Timing
    1. In temperate climates, hand-foot-mouth occurs between Spring and Fall (with occassional winter cases)
    2. In tropical climates, Hand-Foot-Mouth Disease may occur year round
  3. Most common under age 10 years old (esp. under age 5 years old)
  4. Adults caring for ill children may also contract Hand-Foot-Mouth Disease

III. Etiology

  1. Typical childhood presentation
    1. Coxsackie Virus A16 (Enterovirus)
    2. Enterovirus 71
      1. Has been associated with severe cases with Encephalitis, Myocarditis
  2. Atypical presentation seen in adults and teenagers (Coxsackie Virus A6)
    1. Affects teens and adults and is highly contagious via droplets, fecal oral route
    2. More severe presentation with fever, Arthralgias, flu-like symptoms
    3. Diffuse Vesicles, bullae and erosions affect the nose, cheeks, extensor arms, elbows, thighs, buttocks, groin

IV. Pathophysiology

  1. Enteroviral exanthem
  2. Transmission
    1. Fecal-oral transmission
    2. Oral-oral transmission
    3. Respiratory droplets
    4. Higher risk of transmission in regions where access to clean water is limited
  3. Incubation: 3-6 days
  4. Infectivity
    1. Increased in first week of illness
    2. Stool shedding of virus may persist for up to 8 weeks
    3. Household transmission >50%

V. Symptoms

  1. Upper Respiratory Infection symptoms precede oral and skin lesions by days
  2. Low-grade fever
  3. Malaise
  4. Pharyngitis
  5. Rash on palms, soles and buttocks
  6. Decreased oral intake (risk of Dehydration)

VI. Signs

  1. Oral Lesions
    1. Football shaped, painful Vesicles
    2. Involves Soft Palate, Buccal mucosa, Gingiva and Tongue
      1. Spares the posterior pharynx
      2. Contrast with Herpangina which spares the anterior pharynx
  2. Typical Skin lesions
    1. First: Red Papules (2-6 mm) with red halo
    2. Next: Gray Vesicles (may appear as targets)
    3. Next: Vesicles rupture and leave painless shallow ulcers
    4. Last: Lesions heal without scarring after 7-10 days
    5. Distribution: Palms, soles and buttocks
  3. Atypical Skin Lesions (esp. teen and adult cases with Coxsackie Virus A6)
    1. Purpura, Bullae and Pustules may occur
    2. Palm and Sole Desquamation may also occur
    3. Distribution may extend to trunk, cheek, genitalia

VII. Differential Diagnoses

  1. See Hand Dermatitis or Foot Dermatitis
  2. See Oral Ulcer
  3. Aphthous Ulcer
  4. Varicella Virus
  5. Rickettsial Pox (East Coast, U.S.)
  6. Primary Herpetic Gingivostomatitis (Oral Herpes Simplex Virus)
    1. Diffuse involvement seen with Eczema herpeticum (ill patients that typically require admission)
    2. External Vesicles were only typically seen with HSV and varicella
      1. Not seen with Herpangina or Hand Foot and Mouth Disease in past
      2. However, Coxsackie Virus A6 is associated with more diffuse vessicles
  7. Herpangina
    1. Vesicles in posterior pharynx, sparing anterior pharynx
    2. No skin involvement
  8. Erythema Multiforme Major
  9. Kawasaki Disease
  10. Behcet's Syndrome
  11. Pemphigus Vulgaris

VIII. Management

  1. Symptomatic therapy with relief of pain, antipyretics (Acetaminophen, Ibuprofen)
  2. Topical Lidocaine is not recommended in children due to only transient relief and potential for adverse effects
  3. Maintain hydration
  4. Severe illness has occurred (esp. Coxsackie Virus A6, Enterovirus 71) with significant morbidity and mortality
    1. Consider hospital observation stay in severe cases (esp. neurologic changes, cardiopulmonary involvement)
    2. In Asia, IV IG has been used in life threatening cases (evidence is lacking as of 2019)

IX. Complications: Rare

  1. Neurologic Complications (Enterovirus 71)
    1. Aseptic Meningitis
    2. Acute Flaccid Paralysis
    3. Encephalomyelitis
  2. Cardiopulmonary Complications
    1. Pulmonary Edema
    2. Pulmonary Hemorrhage

X. Prognosis

  1. Typically self-limited and children overall do well with basic supportive home care
  2. However, some outbreaks have occurred with increased mortality
    1. Liu (2015) Rev Med Virol 25(2):115-28 [PubMed]

XI. Prevention

  1. Frequent Handwashing is most effective prevention
    1. Wash with soap and water after diaper changes and after urinating or stooling
    2. Wash with soap and water before eating
  2. Disinfect counter tops and toys
  3. Do not share utensils, cups, plates, bowls, food or drinks with infected patients
  4. Breast Feeding is unrelated to transmission and may be continued throughout illness
  5. Children may continue to attend daycare if they may be adequately cared for in that setting
    1. Daycare exclusion does not reduce transmission

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