Palmar and Plantar Pruritus with Swelling in a 39-Year-Old Woman
Immediate Clinical Assessment
Start by determining if this is pregnancy-related, as intrahepatic cholestasis of pregnancy (ICP) is a critical diagnosis that requires urgent intervention in pregnant women. If the patient is pregnant, ICP should be the primary consideration, as it presents with generalized pruritus predominantly affecting palms and soles, typically without a rash, and carries significant fetal risk including stillbirth 1.
Key Differential Diagnoses
The differential diagnosis for palmar-plantar pruritus with swelling includes:
Dyshidrotic eczema (pompholyx): Characterized by pruritic, tense vesicles on palms, soles, and lateral finger surfaces, often associated with hyperhidrosis and occurring in spring allergy season 2. This presents with "ferocious pruritus" and vesicles embedded in the epidermis that are painful when enlarged 3.
Palmoplantar psoriasis: Can present with pustules on an erythematous background affecting palms and soles, often debilitating and painful despite small body surface area involvement 1.
Contact dermatitis: Type IV delayed hypersensitivity reaction to topical agents including antihistamines, antibiotic ointments, local anesthetics, or cosmetic preservatives 4.
Drug-induced reaction: Systemic medications can cause nonspecific pruritus or maculopapular eruptions; isolated palmar-plantar itching has been reported as a rare allergic reaction to certain medications including vaccines 5, 4.
Metal allergy-related dyshidrotic eczema: Metal allergy is an important etiologic factor, with improvement noted when metal allergen is removed 2.
Intrahepatic cholestasis of pregnancy (if pregnant): Pruritus worse at night, predominantly affecting palms and soles, without rash initially 1.
Mycosis fungoides palmaris et plantaris: Rare cutaneous T-cell lymphoma variant that mimics dyshidrotic eczema but persists despite topical corticosteroid treatment 6.
First-Line Treatment Algorithm
Step 1: Initial Conservative Management
Begin with intensive emollient therapy using urea-containing moisturizers (5-10%) for skin barrier restoration, applied liberally and frequently 7.
Add high-potency topical corticosteroids twice daily to affected areas for inflammatory control 8.
Prescribe oral nonsedating antihistamines for pruritus relief (avoid sedating antihistamines, especially in elderly patients) 1, 8.
Step 2: Trigger Avoidance
Avoid frequent washing with hot water, skin irritants, prolonged walking, tight socks, and mechanical stress to affected areas during the acute phase 8, 7.
Identify and eliminate potential contact allergens including topical medications, cosmetics, and occupational exposures 4.
Consider patch testing for metal allergy if dyshidrotic eczema is suspected 2.
Step 3: Escalation if No Response in 2 Weeks
If symptoms persist despite initial management:
For palmoplantar psoriasis: Consider targeted phototherapy (308-nm excimer laser) or soak PUVA (15-30 minutes in methoxsalen solution) 1.
For moderate disease with systemic symptoms: Oral prednisone 0.5-1 mg/kg daily may be used 8.
For severe palmoplantar psoriasis unresponsive to topical therapy: Systemic therapy with methotrexate, cyclosporine, or oral retinoids should be considered, though retinoids are contraindicated in women of childbearing potential due to teratogenicity 1.
Critical Pitfalls to Avoid
Do not dismiss persistent lesions as simple eczema: If topical corticosteroids fail after 2-4 weeks, consider skin biopsy to rule out mycosis fungoides palmaris et plantaris 6.
Do not use TNF antagonists for chronic palmoplantar pustulosis: This condition shows almost complete lack of benefit from TNF antagonists and may paradoxically worsen 1.
Do not overlook pregnancy status: Missing ICP diagnosis can result in fetal death; check total bile acid levels if pregnant 1.
Do not prescribe acitretin to women of childbearing potential: FDA mandates 3-year post-dosing moratorium on pregnancy 1.
When to Refer to Dermatology
Refer urgently if: