Hand, Foot, and Mouth Disease

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Etiology & Epidemiology - Tiny Viral Attackers

  • Causative Agents: Picornaviridae family.
    • Coxsackievirus A16 (CVA16): Most common.
    • Enterovirus 71 (EV-A71): Linked to severe neurological issues.
    • Other Coxsackie A/B, Echoviruses.
  • Epidemiology:
    • Age: Primarily children < 5-10 years.
    • Transmission: Faecal-oral (main), respiratory droplets, direct contact (vesicles, fomites).
    • Incubation: 3-6 days.
    • Seasonality (India): Summer & monsoon peak.
    • Communicability: Highest in 1st week; stool shedding for weeks.

⭐ EV-A71 is linked to severe outbreaks with neurological complications, particularly in Asia-Pacific_region_

Clinical Features - Spotting the Spots

  • Incubation Period: 3-6 days.
  • Prodrome (1-2 days prior to rash):
    • Low-grade fever
    • Malaise, anorexia
    • Sore throat/mouth, abdominal pain
  • Enanthem (Oral Lesions): Often first sign.
    • Painful vesicles → erosions/ulcers (aphthae-like).
    • Location: Tongue, buccal mucosa, hard palate, gums, lips.
    • May cause drooling, refusal to eat.
  • Exanthem (Skin Rash): Appears 1-2 days after enanthem.
    • Vesicles (oval, greyish, thin-walled) on an erythematous base.
    • Characteristic distribution:
      • Hands (palms > dorsa)
      • Feet (soles > dorsa)
      • Buttocks (common, especially in diaper area)
    • Less common: Knees, elbows, perineum.
    • Typically non-pruritic, but can be tender.
    • Heals in 7-10 days without scarring.

HFMD Vesicular Rash on Fingers

Atypical HFMD (often Coxsackievirus A6): More widespread/severe rash, can be vesiculobullous, petechial, or purpuric. May involve trunk, limbs, face. Onychomadesis (nail shedding) can occur 1-2 months later.

Complications - Danger Zones

  • Usually mild; severe forms rare (esp. EV-A71).
  • Severe (EV-A71 associated):
    • Aseptic meningitis
    • Encephalitis (brainstem)
    • Acute flaccid paralysis (AFP)
    • Myocarditis, pulmonary edema
  • Common:
    • Dehydration (painful oral ulcers)
    • Onychomadesis (nail shedding 1-2 months post-infection)
    • Secondary skin infection

⭐ Enterovirus A71 (EV-A71) is notorious for causing severe neurological complications (e.g., brainstem encephalitis) and fatalities in HFMD outbreaks.

Diagnosis & DDx - Detective Work

  • Clinical Diagnosis: Primarily by typical rash:
    • Oral: Painful vesicles/ulcers (tongue, buccal mucosa).
    • Skin: Vesicles on palms, soles, buttocks.
    • Prodrome: Mild fever.
  • Lab (Usually not required): Viral culture, PCR, serology.
  • Differential Diagnosis (DDx):
ConditionKey Differentiators from HFMD
HerpanginaOral ulcers (posterior pharynx); NO hand/foot lesions.
Aphthous StomatitisRecurrent oral ulcers; NO fever or exanthem.
VaricellaGeneralized rash (truncal focus); lesions in crops.
Herpetic GingivostomatitisSevere oral pain, friable gums; perioral vesicles.

Management & Prevention - Care & Shield

  • Supportive Care:
    • Analgesics & antipyretics (paracetamol, ibuprofen) for pain/fever.
    • Topical anesthetics (e.g., benzydamine, lidocaine gel) for oral ulcers.
    • Adequate hydration; soft, non-irritating foods.
  • Prevention:
    • Good hygiene: frequent handwashing.
    • Disinfect contaminated surfaces.
    • Avoid close contact with infected individuals.
    • Isolate infected children from school/daycare until fever resolves and lesions heal.

Complication Watch: Neurological complications (e.g., aseptic meningitis, encephalitis), though rare, are more associated with Enterovirus 71 (EV-A71) infections. Monitor for severe headache, stiff neck, or altered sensorium.

High‑Yield Points - ⚡ Biggest Takeaways

  • Caused by Coxsackievirus A16 (common) and Enterovirus 71 (severe, neuro complications).
  • Features painful oral vesicles (enanthem) and maculopapular/vesicular rash on hands, feet, buttocks.
  • Spreads via fecal-oral and respiratory routes; highly contagious.
  • Predominantly affects children under 5 years.
  • Diagnosis is clinical. Dehydration is a common complication.
  • EV-A71 strains can lead to aseptic meningitis or encephalitis.
  • Management is symptomatic and supportive (hydration, analgesics).

Practice Questions: Hand, Foot, and Mouth Disease

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Hand-foot-mouth disease is caused by:

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Flashcards: Hand, Foot, and Mouth Disease

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_____ is a dermatological infection caused byEBV in that commonly presents on the lateral tongue.

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_____ is a dermatological infection caused byEBV in that commonly presents on the lateral tongue.

Hairy Leukoplakia

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