How should I evaluate and manage a patient with a rash limited to the palms?

Evaluation and Management of Palmar Rash

Immediately initiate empiric doxycycline 100 mg twice daily if the patient has fever, headache, or systemic symptoms alongside the palmar rash, as Rocky Mountain Spotted Fever (RMSF) carries a 5-10% mortality rate and petechial involvement of palms indicates advanced disease. 1

Immediate Life-Threatening Diagnoses to Exclude

Rule out RMSF first, even without the classic triad of fever, rash, and tick exposure—only a minority present with all three initially. 1

• RMSF typically begins 2-4 days after fever onset with small blanching pink macules on ankles, wrists, or forearms that evolve to maculopapular lesions with central petechiae 1, 2
• Petechial involvement of palms and soles indicates advanced disease and severe illness 1, 3
• Up to 40% of patients report no tick bite history, and up to 20% never develop a rash 1, 2
• 50% of deaths occur within 9 days of illness onset 1
• Start doxycycline immediately without waiting for confirmatory testing 1

Consider meningococcemia if petechial or purpuric rash is present with high fever, severe headache, or altered mental status. 1, 3

• Progresses more rapidly than RMSF and can lead to purpura fulminans 1, 3
• Add ceftriaxone 2 g IV every 12-24 hours if meningococcemia cannot be excluded 1
• Up to 50% of early cases lack rash 1

Evaluate for secondary syphilis, which causes maculopapular rash involving palms and soles with oral mucous patches. 1, 3

• Less acute presentation than RMSF or meningococcemia but requires identification 1
• Obtain RPR/VDRL and treponemal-specific testing 1

Systematic Diagnostic Approach

Step 1: Assess for Systemic Toxicity

Immediately hospitalize if any of the following are present: 1

• Fever, tachycardia, confusion, hypotension, or altered mental status 1
• Rapidly progressive rash 1
• Generalized petechiae or purpuric rash 1

Step 2: Obtain Focused History

Key historical elements to elicit: 1, 2

• Recent outdoor activities in grassy/wooded areas (RMSF peaks April-September) 1, 2
• Tick exposure (present in only 60% of RMSF cases) 1
• Recent medications, particularly chemotherapy agents 4
• Cardiac risk factors for endocarditis 1
• Sexual history for syphilis risk 1

Step 3: Characterize the Rash Morphology

Petechial/purpuric rash on palms: 1, 3

• RMSF (advanced disease with central petechiae in maculopapular lesions) 1, 3
• Meningococcemia (rapidly progressive petechiae/purpura) 1, 3
• Bacterial endocarditis 1, 3
• Secondary syphilis (less commonly petechial) 3

Maculopapular rash on palms: 1, 2

• Secondary syphilis (classic presentation) 1, 3
• RMSF (early stage before petechiae develop) 1, 2
• Viral exanthems (enteroviral infections typically spare palms) 2
• Drug hypersensitivity reactions 3, 5

Erythema with dysesthesia/burning on palms: 4

• Hand-foot syndrome (palmar-plantar erythrodysesthesia) from chemotherapy agents including 5-fluorouracil, capecitabine, doxorubicin, or cytarabine 4
• Hand-foot skin reaction from BRAF inhibitors or multikinase VEGFR inhibitors (sorafenib, sunitinib, regorafenib) with painful hyperkeratosis 4

Eczematous/irritant dermatitis on palms: 4

• Irritant contact dermatitis from frequent hand washing, sanitizers, or occupational exposures 4
• Allergic contact dermatitis from glove accelerators, preservatives, or fragrances 4

Step 4: Obtain Essential Laboratory Studies

For suspected infectious etiologies: 1, 2

• Complete blood count with differential (thrombocytopenia, leukopenia, bandemia suggest RMSF/ehrlichiosis) 1, 2
• Comprehensive metabolic panel (hyponatremia, elevated hepatic transaminases in RMSF) 1, 2
• Blood cultures before antibiotics if endocarditis suspected 1
• Peripheral blood smear 1
• Acute serology for Rickettsia rickettsii, Ehrlichia chaffeensis, Anaplasma phagocytophilum 2
• RPR/VDRL and treponemal testing for syphilis 1

Management by Etiology

Rocky Mountain Spotted Fever

Initiate doxycycline 100 mg PO/IV twice daily immediately for adults. 1

• Continue for at least 3 days after fever subsides and until clinical improvement, typically 5-7 days minimum 1
• Clinical improvement expected within 24-48 hours 2
• Do not delay treatment for laboratory confirmation 1

Chemotherapy-Induced Hand-Foot Syndrome

For grade 1-2 (mild to moderate symptoms): 4

• Continue chemotherapy at current dose and monitor 4
• Apply topical low/moderate strength corticosteroids 4
• Reassess after 2 weeks 4

For grade ≥3 (severe symptoms limiting self-care): 4

• Interrupt chemotherapy until symptoms improve to grade 0-1 4
• Apply topical corticosteroids 4
• Consider systemic corticosteroids (prednisone 0.5-1 mg/kg for 7 days) 4
• Dose reduction or discontinuation may be necessary if no improvement 4

Irritant/Allergic Contact Dermatitis

For irritant contact dermatitis: 4

• Identify and avoid irritants (frequent hand washing, harsh soaps, hot water) 4
• Apply moisturizer after hand washing and before wearing gloves 4
• Use water-based moisturizers under gloves 4
• Apply topical corticosteroids if conservative measures fail 4
• Consider "soak and smear" technique: soak hands in plain water for 20 minutes, then immediately apply moisturizer to damp skin nightly for up to 2 weeks 4

For allergic contact dermatitis: 4

• Use accelerator-free gloves (neoprene or nitrile) 4
• Apply moisturizer before wearing gloves 4
• Consider cotton glove liners 4
• Patch testing should be performed for recalcitrant cases 4
• Apply topical corticosteroids to mitigate flares 4

Critical Pitfalls to Avoid

Do not wait for the classic triad of fever, rash, and tick bite in RMSF—it is present in only a minority of patients at initial presentation. 1, 2

Absence of rash elsewhere does not exclude serious disease—up to 20% of RMSF cases never develop a rash. 1, 2

Rash on palms is not pathognomonic for any single condition—maintain a broad differential including RMSF, meningococcemia, secondary syphilis, endocarditis, and drug reactions. 1, 3

In darker-skinned patients, petechial rashes may be difficult to recognize, increasing risk of delayed diagnosis. 1, 3

Do not delay empiric antibiotic treatment for laboratory confirmation in suspected RMSF or meningococcemia—delayed treatment is the most important factor associated with death. 1, 2

Viral exanthems during antibiotic therapy can mimic drug hypersensitivity and lead to unnecessary lifelong antibiotic avoidance—confirm viral etiology when possible. 6, 7