What is the diagnosis and treatment for red and brown macules on the palms and soles?

Red and Brown Macules on Palms and Soles: Diagnosis and Treatment

Immediate Life-Threatening Assessment

If the patient has fever, headache, or recent tick exposure (within 2 weeks), immediately initiate doxycycline for presumed Rocky Mountain spotted fever (RMSF) before awaiting diagnostic confirmation, as mortality increases from 5-10% to potentially fatal with treatment delay. 1

Critical Red Flags Requiring Urgent Action

• RMSF presents with maculopapular rash spreading to palms and soles 2-4 days after fever onset, though 10-15% never develop a rash—do not wait for the classic triad of fever, rash, and tick bite before treating. 1

• Doxycycline should be continued for at least 3 days after fever subsides and until clinical improvement, typically 5-7 days total. 1

• In pregnant patients, measure serum bile acids immediately to exclude intrahepatic cholestasis of pregnancy, which predominantly affects palms and soles with pruritus worse at night and carries stillbirth risk. 1

• Check for recent medication exposure (within 1-3 weeks) to rule out Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN), which requires immediate discontinuation of causative medications and transfer to burn unit or ICU. 1

Systematic Diagnostic Algorithm for Non-Emergent Cases

Step 1: Assess for Systemic Symptoms

• Fever + palmar/plantar rash + tick exposure = empiric doxycycline for RMSF 1

• Fever + headache + rash in 30% adults/60% children = consider ehrlichiosis (3% case-fatality rate) 1

• Children with fever ≥5 days + erythema/induration of palms/soles = evaluate for Kawasaki disease, which requires at least 4 of 5 principal criteria (extremity changes, polymorphous exanthem, bilateral conjunctival injection, oral/lip changes, cervical lymphadenopathy). 1

Step 2: Medication and Chemotherapy History

• Chemotherapy-induced hand-foot syndrome occurs in 6-60% of patients on capecitabine, 5-FU (6-34%), doxorubicin (22-29%), or PEGylated liposomal doxorubicin (40-50%), presenting with redness, marked discomfort, swelling, and tingling within days to weeks. 2

• For Grade 1-2 hand-foot syndrome: continue drug and apply topical low/moderate potency steroid. 2

• For Grade ≥3: interrupt treatment until Grade 0/1, use doxycycline 100mg twice daily for 6 weeks, topical steroids, and consider systemic corticosteroids. 2

Step 3: Infectious Causes Without Systemic Symptoms

• Secondary syphilis presents with red-brown macules on palms and soles—treat with benzathine penicillin G 2.4 million units IM single dose for early syphilis, or doxycycline 100mg PO twice daily for 14 days if penicillin-allergic and not pregnant. 1

• Tinea nigra causes asymptomatic, unilateral, well-defined brown to black macules predominantly on palms—diagnose with KOH preparation showing pigmented yeast and hyphae, treat with topical ketoconazole with complete resolution within 2 weeks to 1 month. 3

Step 4: Dermatologic Conditions

• Palmoplantar psoriasis requires high-potency topical corticosteroids under occlusion as first-line treatment, with combination vitamin D analogues for enhanced efficacy. 4

• For severe palmar psoriasis: oral acitretin 25mg daily shows substantial improvement within 2 months, though requires 3-year post-dosing pregnancy restriction in women of childbearing potential. 4

• Alternative therapies include 308-nm excimer laser or soak PUVA 2-3 times weekly for several months. 4

• Irritant contact dermatitis from frequent handwashing (especially during COVID-19 precautions) or water >40°C—treat with moisturizer after every hand wash using lukewarm water and moderate-to-high potency topical corticosteroids. 2

Step 5: Benign Pigmented Lesions

• Volar melanotic macules appear as asymptomatic tan-brown to brownish-black macules on palms/soles, more common in dark-skinned individuals but can occur in light-skinned patients with chronic hand dermatitis or inflammatory conditions. 5

• These benign lesions show purely epidermal hyperpigmentation without increased melanocyte number and may be associated with Laugier-Hunziker syndrome (macular hyperpigmentation of nail, volar, and mucosal surfaces in healthy adults). 5

Common Pitfalls to Avoid

• Never wait for complete clinical presentation before treating suspected RMSF—only a minority present with all three components (fever, rash, tick bite) initially, and delayed treatment dramatically increases mortality. 1

• Do not dismiss palmar/plantar involvement as benign—this specific distribution significantly narrows the differential to RMSF, secondary syphilis, Kawasaki disease (children), ehrlichiosis, and rat bite fever. 1

• Children under 15 years develop RMSF rash more frequently and earlier than adults, requiring higher clinical suspicion. 1

• Palmar psoriasis significantly impacts quality of life, justifying systemic therapy use rather than prolonged ineffective topical treatment. 4