What are key questions to ask in the history and differential diagnoses for a patient with palmar eczema?

History and Differential Diagnoses for Palmar Eczema

Essential History Questions

When evaluating palmar eczema, systematically inquire about occupational and environmental exposures, as the pattern and morphology alone cannot reliably distinguish between atopic, irritant, and allergic etiologies. 1

Atopic and Personal History

• Personal history of childhood atopic dermatitis, asthma, or hay fever 1
• Family history of atopic disease in first-degree relatives 1
• History of general dry skin in the past year 1
• Age of onset (atopic eczema typically begins in first two years of life, though palmar involvement may develop later) 1

Occupational and Environmental Exposures

• Detailed occupational history: What specific materials, chemicals, or products are handled at work? Request health and safety data sheets 1
• Temporal relationship to work: Do symptoms improve on weekends and holidays, then recur upon return to work? 1
• Frequency of hand washing and wet work exposure (water itself is an irritant) 1
• Use of gloves: Type, frequency, and whether symptoms occur inside gloves 1
• Recreational activities: Home improvements, painting, decorating, gardening, sports 1

Product and Allergen Exposure

• All wash products used: Soaps, detergents, hand sanitizers (most contain harsh surfactants that damage skin barrier) 1
• Cosmetics and personal care products applied to hands 1
• Topical medications, creams, or ointments used (including over-the-counter products) 1
• Contact with specific materials: Rubber gloves, metals (nickel, chromate, cobalt), fragrances, preservatives 1
• Clothing and accessories: Rings, watches, bracelets 1

Symptom Characteristics and Triggers

• Initial location of symptoms and subsequent spread pattern 1
• Presence and severity of pruritus 1
• Sleep disturbance from itching 1
• Relationship to sunlight exposure (photoaggravated dermatitis) 1
• Aggravating factors and specific triggers identified by patient 1

Treatment History and Response

• All previous treatments tried and their effectiveness 1
• Current and past use of topical corticosteroids (potency, duration, frequency) 1
• Use of systemic steroids or other immunosuppressants 1
• Emollient use: Type, frequency, and quantity 1

Impact Assessment

• Effect on work performance and ability to perform job duties 1
• Impact on daily activities and quality of life 1
• Patient's most distressing symptom 1
• Patient and family expectations from treatment 1

Red Flag Symptoms Requiring Urgent Evaluation

• Sudden deterioration in previously stable eczema (suggests secondary infection or new contact allergen) 1
• Crusting, weeping, or honey-colored discharge (bacterial superinfection) 1, 2
• Multiple uniform "punched-out" erosions or grouped vesicles (eczema herpeticum—a dermatologic emergency) 1, 2, 3
• Systemic symptoms: Fever, malaise, lymphadenopathy (though lymphadenopathy alone may be reactive in extensive eczema) 1

Primary Differential Diagnoses

Dyshidrotic Eczema (Pompholyx)

• Recurrent vesicular eruption affecting palms and/or soles with characteristic "tapioca pudding" appearance on examination 4
• Intensely pruritic with sudden onset 4
• More common in young to middle-aged adults, affects men and women equally 4
• May be associated with atopy (42% have atopic history), contact allergy (73% have positive patch tests), or fungal/microbial allergy 5

Irritant Contact Dermatitis

• More common than allergic contact dermatitis but pattern alone cannot distinguish them 1
• History of frequent wet work, hand washing, or exposure to harsh chemicals 1
• Cumulative damage from repeated low-grade irritant exposure 1

Allergic Contact Dermatitis

• Carries worse prognosis than irritant dermatitis unless allergen identified and avoided 1
• Common allergens include nickel (14.5%), fragrances (37%), cobalt (22%), chromate, epoxy resin 1
• Occupational allergens in food handlers (proteins from vegetables, meats, fish), bakers (flour, enzymes), hairdressers 1
• Requires patch testing for definitive diagnosis, as clinical appearance is unreliable 1

Atopic Hand Eczema

• Personal or family history of atopy (eczema, asthma, hay fever) 1
• General dry skin and history of flexural eczema 1
• May coexist with contact dermatitis (either irritant or allergic) 1

Hyperkeratotic Palmar Eczema (Eczema Keratoticum)

• Chronic hyperkeratotic changes with painful fissures affecting palms and volar fingers 6
• More common in middle-aged persons 6
• May have similar plantar involvement 6

Tinea Manuum

• Fungal infection that can mimic eczema 5
• Typically unilateral ("one hand, two feet" pattern is classic) 5
• Requires KOH preparation or fungal culture for diagnosis 5

Psoriasis

• Well-demarcated plaques with silvery scale (though palmar psoriasis may lack typical scale)
• Look for nail changes (pitting, onycholysis) and involvement at other sites
• Family history of psoriasis

Secondary Bacterial Infection (Impetiginized Eczema)

• Crusting, weeping, honey-colored exudate 1, 2
• Staphylococcus aureus most common pathogen 1
• Send swabs for bacterial culture if suspected 1

Eczema Herpeticum

• Multiple uniform "punched-out" erosions or vesiculopustular eruptions very similar in shape and size 2, 3
• Medical emergency requiring immediate systemic acyclovir 3
• May progress rapidly to systemic infection without antiviral therapy 3
• Send viral swab and smear for electron microscopy if suspected 1

Critical Examination Findings

• Record extent and severity of eczema using validated tools (Hand Eczema Severity Index) 1
• Document distribution pattern: Palmar only, volar fingers, dorsal hands, wrists 1
• Assess for vesicles, scaling, hyperkeratosis, fissuring, erythema 1, 6
• Look for evidence of infection: Crusting, weeping, pustules, uniform erosions 1, 2
• Examine other body sites for eczema or psoriasis 1
• Check nails for changes (should be kept short in eczema patients) 1

Common Pitfalls to Avoid

• Do not rely on morphology alone to distinguish atopic from contact dermatitis—patch testing is essential when contact allergy is suspected 1
• Do not assume palmar eczema is purely endogenous/atopic without thoroughly investigating occupational and environmental exposures 1
• Do not delay bacterial or viral swabs in deteriorating eczema—secondary infection is common and requires specific treatment 1
• Do not miss eczema herpeticum—this is a true dermatologic emergency requiring immediate systemic antivirals 2, 3
• Do not forget that contact dermatitis can develop in patients with pre-existing atopic eczema 1