Chronic Irritant Contact Paronychia with Beau's Lines
The most likely cause is chronic irritant contact dermatitis from repeated wet work exposure, leading to chronic paronychia with secondary nail matrix inflammation that produces the horizontal ridges (Beau's lines). 1, 2
Pathophysiology in Occupational Context
The dishwasher occupation is the critical diagnostic clue here. Chronic paronychia develops through a specific mechanism in wet-work occupations:
- Repeated water immersion causes swelling and detachment of the protective cuticle from the nail plate, breaking the water-tight seal and allowing irritants, detergents, and microorganisms to enter the subcuticular space 1
- This creates a vicious cycle where chronic inflammation in the proximal nail fold and nail matrix region produces the horizontal ridging (Beau's lines) as the nail grows out 1, 3
- The condition is multifactorial inflammatory reaction to irritants and allergens, not primarily an infection, though secondary colonization with Candida or bacteria occurs in up to 56% of cases 2, 4
Clinical Features Supporting This Diagnosis
The presentation described fits the classic pattern:
- Redness, swelling, and tenderness of the lateral nail folds are hallmark features of chronic paronychia 2, 5
- Horizontal ridges (Beau's lines) indicate nail matrix involvement from the chronic inflammation extending proximally 1, 3
- Housewives, dishwashers, bartenders, and florists are the most commonly affected occupational groups, with frequent hand washing being the predominant risk factor in 80% of cases 2, 5, 4
- Female predominance (82.5%) and housewives (58.8%) are typical, though this male dishwasher fits the occupational exposure pattern 4
Key Distinguishing Features
This is NOT primarily a fungal infection, despite common misconceptions:
- Chronic paronychia was historically misattributed to Candida infection but is now recognized as an irritant/allergic dermatitis of the nail fold 2, 4
- When Candida is present (positive culture in 56% of cases), it represents secondary colonization or hypersensitivity reaction rather than primary infection 4
- The proximal nail fold inflammation and loss of cuticle barrier are the primary pathology, with fibrosis developing from repeated inflammatory episodes 2
Management Algorithm
Immediate interventions:
- Identify and eliminate irritant exposure: wearing cotton-lined waterproof gloves during all wet work is essential 1, 5
- Apply mid-to-high potency topical corticosteroid ointment to nail folds twice daily as first-line therapy, which has proven more effective than antifungals 2, 5
- Daily application of topical emollients to cuticles and periungual tissues to restore barrier function 1, 6
If inadequate response after 2-4 weeks:
- Consider patch testing for contact allergens (positive in 27% of chronic paronychia cases, with nickel most common) 1, 4
- Consider topical calcineurin inhibitors as steroid-sparing alternatives for prolonged therapy 5
- Prick testing for Candida hypersensitivity may be warranted (positive in 48% of cases) 4
For refractory cases:
- Surgical options include en bloc excision of proximal nail fold or eponychial marsupialization, though this is rarely needed with proper occupational modification 2
Critical Pitfalls to Avoid
- Do not treat empirically with antifungals without mycological confirmation—50% of dystrophic nails are non-fungal, and topical steroids are more effective for chronic paronychia than antifungals 6, 2
- Do not overlook occupational counseling—treatment will fail without eliminating the causative wet-work exposure through protective gloves and work modification 1, 5
- Avoid confusing with acute bacterial paronychia, which presents with rapid onset, purulent discharge, and abscess formation requiring drainage 5, 3
- Treatment requires weeks to months—patient education about the chronic nature and need for sustained barrier protection is paramount to prevent recurrence 5, 3