What are the characteristics of a hand, foot, and mouth rash?

Describing the Hand, Foot, and Mouth Disease Rash

The hand, foot, and mouth disease rash presents as small pink macules that evolve into vesicular lesions with a highly characteristic distribution on the palms and soles, accompanied by painful oral ulcerations. 1

Primary Rash Characteristics

Distribution Pattern

• Vesicles appear on palms and soles as the hallmark feature, with this palmoplantar distribution being the defining characteristic that distinguishes HFMD from other viral exanthems 1
• The oral cavity develops painful vesiculoulcerative lesions (enanthem) that occur simultaneously with the skin eruption 2
• The rash may extend to the dorsum of hands and feet in some cases 3

Morphology and Evolution

• Lesions begin as small pink macules that rapidly progress to vesicular lesions within hours to days 1
• The vesicles are typically deep-seated, erythematous, and may appear as papules on examination 4
• Individual lesions are usually asymptomatic despite their appearance, though oral lesions cause significant pain 4, 5
• The vesicles may be subtle and require magnification to visualize in some cases—fatal cases have been reported with only 1-2 mm punctate sub-epidermal vesicles visible only with a magnifying glass 6

Prodromal Features

• Fever is the first symptom, typically low-grade but can exceed 102.2°F (39°C), accompanied by malaise, sore throat, and irritability 1
• Respiratory symptoms including cough and rhinitis may accompany the classic presentation 1
• The rash typically appears 1-2 days after fever onset 5

Critical Distinguishing Features from Other Conditions

Versus Kawasaki Disease

• HFMD presents with vesicular lesions, not diffuse erythema as seen in Kawasaki disease 1, 7
• Kawasaki shows erythema and edema of palms/soles with subsequent periungual desquamation at 2-3 weeks but lacks vesicles entirely 7
• HFMD does not present with the persistent high fever (≥5 days) or strawberry tongue characteristic of Kawasaki disease 1

Versus Chickenpox

• HFMD vesicles are concentrated on hands, feet, and mouth rather than being widely distributed across the trunk and face 1

Versus Drug Reactions

• Drug hypersensitivity reactions can cause palmoplantar involvement but lack the characteristic vesicular morphology of HFMD 7
• Chemotherapy-induced hand-foot syndrome presents with dysesthesia, burning pain, and hyperkeratosis rather than discrete vesicles 8

Versus Infectious Mimics

• Rocky Mountain spotted fever presents with blanching pink macules evolving to petechiae, not vesicles 7
• Meningococcal infection shows petechial/purpuric rash, not vesicular lesions 9
• Syphilis can affect palms and soles but presents with copper-colored macules or papules, not vesicles 1

Associated Findings

• Nail dystrophies (Beau's lines or onychomadesis) may occur weeks after initial symptom onset as a late complication 3, 4
• The rash is typically self-limited, resolving in 7-10 days without treatment 5
• Mucosal involvement is common, but some cases present with minimal or no oral lesions 4, 6

Common Pitfalls

• Do not dismiss subtle presentations—fatal cases have occurred with minimal skin findings visible only under magnification 6
• The absence of oral lesions does not exclude HFMD, as some cases present with skin findings alone 4
• Recurrence is possible despite prior infection, though subsequent episodes tend to be milder 4
• The disease can progress rapidly to neurological and cardiopulmonary complications despite minimal initial skin findings 6