What could cause a single hand to be dry and cracked while the opposite hand appears normal, and how should it be evaluated and managed?

Unilateral Hand Dermatitis: Evaluation and Management

When one hand is dry and cracked while the other remains normal, this strongly suggests an asymmetric exposure pattern causing either irritant or allergic contact dermatitis, and you should immediately investigate for unilateral occupational or habitual exposures (such as dominant hand use, specific tool handling, or contact with particular materials) while initiating aggressive moisturization and mid-potency topical corticosteroids. 1

Why Asymmetry Matters Diagnostically

The unilateral presentation is a critical diagnostic clue that points away from systemic or constitutional causes:

• Asymmetric dermatitis indicates localized exposure rather than endogenous conditions like atopic dermatitis or psoriasis, which typically present bilaterally 1, 2
• Pattern and morphology alone cannot distinguish between irritant and allergic contact dermatitis, but the unilateral distribution strongly suggests an external causative agent 3, 1
• The affected hand is likely your dominant hand or the hand with specific exposure to irritants or allergens 2, 4

Immediate Investigation: Exposure History

Obtain a detailed exposure history focusing specifically on activities performed predominantly with the affected hand:

• Occupational exposures: Does the patient use specific tools, handle chemicals, or perform wet work predominantly with one hand? 1, 4
• Household activities: Cleaning products, dish detergent, gardening chemicals, or specific hobby materials 3
• Hand hygiene patterns: Excessive washing of one hand, use of alcohol-based hand sanitizers, or disinfectant wipes on the affected side 3
• Glove use: Wearing gloves on only one hand, or rubber/latex exposure 3
• Contact with metals: Nickel exposure from tools, jewelry, or work equipment handled predominantly with one hand 2, 4

First-Line Treatment Protocol

Aggressive Moisturization

• Apply 2 fingertip units of moisturizer to the affected hand immediately after washing, using fragrance-free products with petrolatum or mineral oil as the base 3, 1
• Reapply every 3-4 hours and after each hand washing 1, 5
• Use the "soak and smear" technique: Soak the affected hand in plain water for 20 minutes, then immediately apply moisturizer to damp skin nightly for up to 2 weeks 3, 1
• Use moisturizers packaged in tubes rather than jars to prevent contamination 3, 1

Topical Corticosteroids

• Start with triamcinolone 0.1% twice daily for localized disease 1, 5
• Escalate to clobetasol 0.05% twice daily for up to 2 weeks if initial therapy fails or disease is more severe 1, 5
• Consider potential topical steroid-induced damage to the skin barrier with prolonged use 3

Eliminate Irritants

• Replace all soaps and detergents with emollients immediately, as these are universal irritants that perpetuate inflammation 1
• Use lukewarm or cold water for hand washing, as water temperatures above 40°C cause lipid fluidization and increased skin permeability 3
• Avoid washing hands with dish detergent or other known irritants 3, 1
• Do not use disinfectant wipes designed for surface cleaning on skin, as they contain harsh antimicrobial agents like N-alkyl dimethyl benzyl ammonium chloride 3

When to Pursue Patch Testing

Refer for patch testing if:

• No improvement after 2 weeks of appropriate topical steroid therapy and irritant avoidance 1, 5
• Recurrent or chronic dermatitis despite conservative management 1
• Suspected allergic contact dermatitis based on exposure history 1, 5

Common allergens to consider in unilateral hand dermatitis:

• Nickel (most common contact allergen, especially in young females) 2, 6, 4
• Methylisothiazolinone (preservative in hand hygiene products) 2
• Rubber accelerators (in gloves, particularly for healthcare workers) 3, 2
• Formaldehyde and quaternium-15 2, 4
• Fragrance mix 2, 4

Protective Measures During Treatment

• Apply moisturizer before wearing gloves to prevent occlusion-related irritation 3, 1
• Use rubber or PVC gloves with cotton liners for household tasks, removing them regularly to prevent sweat accumulation 3, 1
• For latex allergy, use accelerator-free neoprene or nitrile gloves 3, 1
• Avoid prolonged occlusion without underlying moisturizer application 3, 1

Critical Pitfalls to Avoid

• Do not wash hands immediately before or after using alcohol-based hand sanitizer, as this is unnecessary and increases dermatitis risk 3
• Do not apply gloves when hands are still wet from washing or sanitizer 3
• Do not use very hot or very cold water for hand washing 3, 1
• Do not over-rely on barrier creams alone—they have questionable clinical value and may create false security 3, 1
• Avoid products containing topical antibiotics (neomycin, bacitracin) without clear indication, as these are common allergens 3, 1

Escalation for Refractory Cases

If no improvement after 6 weeks of appropriate therapy:

• Consider topical tacrolimus 0.1% where topical steroids are unsuitable or ineffective 1
• PUVA phototherapy is an established second-line treatment for chronic hand eczema resistant to topical steroids 1
• For severe chronic hand eczema, offer alitretinoin 1
• Consider systemic therapies (azathioprine, ciclosporin, methotrexate) for steroid-resistant cases 1

Prognosis and Long-Term Management

• Only 25% of patients with occupational contact dermatitis achieve complete healing over 10 years, with 50% experiencing intermittent symptoms and 25% having permanent symptoms 1
• Early identification and complete avoidance of the causative agent offers the best chance for resolution 1
• Changing occupation does not improve prognosis in 40% of cases, emphasizing the importance of early intervention 1

Special Consideration: Irritant vs. Allergic Contact Dermatitis

Irritant contact dermatitis (ICD) is more common than allergic contact dermatitis (ACD) in both occupational and non-occupational settings, accounting for 80% of occupational skin disease cases 3, 2. However:

• ICD results from direct chemical or physical damage to the skin barrier from detergents, solvents, or repeated wet work 3
• ACD requires prior sensitization to a specific allergen followed by elicitation upon re-exposure 3
• Clinical features alone cannot reliably distinguish between ICD and ACD, making patch testing essential when the diagnosis remains uncertain 1, 2

The unilateral presentation in your case suggests a specific exposure pattern that should be identifiable through careful history-taking, making successful treatment highly dependent on identifying and eliminating that exposure.