Diagnosis and Management of Secondary Syphilis and Palmoplantar Psoriasis

Critical Diagnostic Considerations

• The American Academy of Dermatology recommends serologic testing for syphilis, including RPR/VDRL and treponemal-specific testing, in patients presenting with symmetric palmoplantar involvement with red-brown macules, due to the high likelihood of secondary syphilis 1, 2
• The Centers for Disease Control and Prevention (CDC) guidelines suggest that the acute onset of lesions over weeks is inconsistent with psoriasis, which typically follows a chronic, stable course or gradual progression 1

Diagnostic Workup and Treatment

• The CDC recommends immediate diagnostic workup, including serologic testing for syphilis and HIV screening, as syphilis and HIV frequently coexist 1, 2
• The American Academy of Dermatology suggests that benzathine penicillin G 2.4 million units IM as a single dose is the standard treatment for secondary syphilis, based on CDC guidelines 1
• The CDC guidelines recommend partner notification and treatment of sexual partners, as well as follow-up serology to confirm treatment response 1

Treatment of Palmoplantar Psoriasis

• The Journal of the American Academy of Dermatology recommends topical regimen, including superpotent topical corticosteroids under occlusion combined with calcipotriene ointment or tazarotene gel, as first-line therapy for palmoplantar psoriasis 3
• The American Academy of Dermatology suggests that systemic retinoids, such as acitretin 25 mg daily, can be used as second-line therapy for palmoplantar psoriasis, with substantial improvement typically within 2 months 2, 3
• The Journal of the American Academy of Dermatology recommends biologic agents, such as adalimumab, infliximab, or ustekinumab, for refractory cases of palmoplantar psoriasis 2, 3

Clinical Pearls

• The American Academy of Dermatology warns that TNF-alpha antagonists can paradoxically induce pustular psoriasis of the palms and soles in patients without prior psoriasis history 3
• The CDC guidelines recommend avoiding systemic corticosteroids as monotherapy in any form of psoriasis, as they can trigger severe flares, including potentially life-threatening generalized pustular psoriasis 2

Treatment of Palmar and Plantar Psoriasis

First-Line and Alternative Therapies

• Topical coal tar and dithranol may provide additional benefit in some cases of palmar and plantar psoriasis, though they are less commonly used due to practical limitations 4, 5
• The American Academy of Dermatology recommends oral acitretin (25 mg daily) as a highly effective treatment for palmar/plantar psoriasis, with substantial improvement expected within 2 months 6, 7
• Soak PUVA therapy (topical psoralen followed by UVA exposure) can be used for palmar and plantar psoriasis, requiring 2-3 times weekly treatments for several months, with a low risk of cutaneous malignancy 6, 7

Systemic Therapy Considerations

• Methotrexate is effective for palmoplantar psoriasis but requires monitoring for hepatotoxicity and bone marrow toxicity 6, 7
• Cyclosporine is effective but should be used with caution due to nephrotoxicity 6, 7
• Biologic agents (such as adalimumab, infliximab, ustekinumab, or TNF-α inhibitors) can be used for refractory cases of palmar and plantar psoriasis 6, 7

Clinical Considerations

• It is essential to distinguish between plaque-type palmoplantar psoriasis and pustular psoriasis of palms/soles, as the latter is a distinct entity with different treatment considerations 4, 5
• Palmoplantar psoriasis can significantly impact quality of life, justifying systemic therapy when topical treatment is inadequate 6, 7
• There is a risk of paradoxical psoriasis induction with TNF-α antagonists, which can cause pustular psoriasis of palms/soles even in patients without prior psoriasis history 6, 7

Management of Palmoplantar Psoriasis (Hands and Lower Extremities)

Assessment & Indication for Systemic Therapy

• Palmoplantar disease causes disproportionate disability relative to body‑surface‑area involvement; systemic therapy is justified even when BSA < 5 %【8】【9】.

First‑Line Intensive Topical Therapy

• Super‑potent (Class 1‑2) topical corticosteroids applied under occlusion (plastic wrap, gloves or socks overnight) are recommended as initial treatment for thick skin of palms and soles【8】【9】.
• Combination with a vitamin D analogue (e.g., calcipotriene) or tazarotene provides synergistic efficacy and should be used together with the corticosteroid【8】【9】.
• The regimen should be continued for 8–12 weeks before declaring treatment failure【8】【9】.

Phototherapy Options (Second‑Line)

• Narrowband UVB phototherapy is highly effective for psoriasis of the trunk and extremities (excluding palms/soles) and is preferred when leg involvement is present【10】.
• Soak PUVA (psoralen immersion of hands/feet followed by UVA exposure) is effective for isolated palmoplantar disease and carries a low risk of cutaneous malignancy on palms/soles【8】【9】.
• Targeted 308‑nm excimer laser can be employed for localized palmoplantar lesions【8】【9】.

Oral Systemic Therapy (Third‑Line)

• Oral acitretin 25 mg daily is highly effective for palmoplantar psoriasis, with substantial improvement expected within approximately 2 months【8】【9】.
• Methotrexate 15–25 mg weekly is an alternative systemic option but requires regular monitoring for hepatotoxicity and bone‑marrow suppression【8】【9】.
• Cyclosporine 2.5–5 mg/kg daily is effective but should be limited to ≤ 1 year because of nephrotoxicity risk【8】【9】.
• Lipid elevations associated with acitretin can be managed with fibrates (for triglycerides) and statins (for cholesterol), avoiding concurrent use due to rhabdomyolysis risk【8】【9】.

Biologic Therapy (Fourth‑Line / Refractory Disease)

• Biologic agents—including TNF‑α inhibitors (adalimumab, infliximab), IL‑17 inhibitors, IL‑12/23 inhibitor (ustekinumab), and IL‑23 inhibitors—are strongly recommended for refractory palmoplantar psoriasis【10】【8】【9】.
• Head‑to‑head studies show IL‑17, IL‑12/23, and IL‑23 inhibitors achieve higher skin‑clearance rates than TNF‑α inhibitors【10】.
• For extensive disease involving the lower extremities beyond the soles, newer IL‑17/IL‑23 pathway inhibitors are preferred over TNF‑α inhibitors【10】.
• TNF‑α antagonists can paradoxically induce pustular psoriasis of palms and soles in patients without prior disease; clinicians should monitor for this rare event【8】【9】.

Special Considerations

• Phototherapy should be prioritized before systemic agents when psoriasis involves the legs (not limited to soles)【10】.
• Screening for psoriatic arthritis is essential; joint involvement favors escalation to biologic therapy【10】【11】.

Monitoring & Safety

• Methotrexate therapy requires periodic complete blood count and liver‑function testing【8】【9】.
• Cyclosporine therapy mandates regular renal‑function assessment and blood‑pressure monitoring; duration should not exceed 1 year【8】【9】.