What is the management for hand, foot, and mouth disease in an 11-year-old female?

Differential Diagnoses for Hand, Foot, and Mouth Disease in an 11-Year-Old Female

The key differentials to consider in an 11-year-old with suspected hand, foot, and mouth disease include erythema multiforme, herpes simplex virus infection (primary herpetic gingivostomatitis), varicella (chickenpox), and measles, with less common considerations being aphthous stomatitis and Stevens-Johnson syndrome. 1

Primary Differential Diagnoses

Erythema Multiforme

• Target lesions with central clearing or dusky centers, typically on extensor surfaces of extremities and palms/soles 1
• Oral involvement presents as erosive mucositis that can be severe, often triggered by HSV infection or medications 1
• Unlike HFMD, lesions are more polymorphic and symmetrically distributed 1

Herpes Simplex Virus (Primary Herpetic Gingivostomatitis)

• Grouped vesicles on an erythematous base, typically confined to gingiva and anterior mouth 1
• More severe gingivitis with bleeding and intense pain compared to HFMD 1
• Lacks the characteristic hand and foot involvement seen in HFMD 1
• Cervical lymphadenopathy is typically more prominent 1

Varicella (Chickenpox)

• "Dewdrop on a rose petal" appearance with vesicles in different stages of healing 1
• Generalized distribution including trunk, scalp, and mucous membranes rather than acral distribution 1
• Lesions appear in crops over several days 1
• More intense pruritus compared to HFMD 1

Measles

• Koplik spots (small white spots with red halos on buccal mucosa) appear before the rash 1
• Maculopapular rash begins on face and spreads cephalocaudally, not acral 1
• Associated with cough, coryza, and conjunctivitis (the "3 Cs") 1
• More severe constitutional symptoms including high fever 1

Key Distinguishing Features of HFMD

Classic Presentation

• Maculopapular or papulovesicular rash specifically on palms and soles 1
• Painful oral ulcerations typically on tongue, buccal mucosa, and hard palate 2
• Low-grade fever (unlike the high fevers of measles or varicella) 1
• Age consideration: While most common under 5 years, HFMD can occur in older children and adults, particularly with CVA6 outbreaks 3, 4

Atypical Presentations to Consider

• Widespread exanthema beyond classic distribution, involving legs and buttocks, particularly with Coxsackievirus A6 2, 3
• Nail dystrophies (Beau's lines or onychomadesis) appearing weeks after initial symptoms 3
• More severe presentations with neurological complications (encephalitis, meningitis, acute flaccid paralysis) particularly with Enterovirus 71 2, 5

Diagnostic Approach

Clinical Diagnosis

• HFMD is primarily a clinical diagnosis based on characteristic distribution pattern 1
• The combination of oral lesions PLUS acral distribution is highly specific 1

Laboratory Confirmation When Needed

• RT-PCR of vesicle fluid is the gold standard with highest viral loads 2
• Respiratory samples or stool specimens can be used as alternatives 2
• Consider testing in severe cases, atypical presentations, or outbreak settings 2, 5

Critical Red Flags Requiring Immediate Evaluation

• Neurological symptoms: altered mental status, severe headache, neck stiffness, weakness, or seizures suggesting EV-71 complications 2, 5
• Cardiopulmonary distress: tachypnea, respiratory distress, or signs of myocardial involvement 5, 6
• Severe dehydration from inability to maintain oral intake 6
• Immunocompromised status requiring closer monitoring 2

Common Pitfalls to Avoid

• Don't dismiss HFMD in older children or adolescents—while less common, it does occur and may present atypically 4
• Don't rely solely on hand/foot involvement—CVA6 can cause widespread rash that may initially suggest other diagnoses 3
• Don't overlook delayed nail changes—counsel families that nail shedding weeks later is a known sequela 3
• Don't assume mild disease—maintain vigilance for neurological complications, particularly in the first week 5, 6