Swelling of the Nail Bed: Causes and Treatment
Primary Causes
Swelling of the nail bed most commonly results from paronychia (acute or chronic), Candida infection, or trauma, with treatment directed at the underlying etiology.
Acute Paronychia
- Acute paronychia develops from direct or indirect trauma to the cuticle or nail fold, allowing pathogen inoculation and resulting in erythematous, painful swelling of the periungual tissue 1
- The posterior nail fold becomes swollen, erythematous, and painful, often with a prominent gap developing between the fold and nail plate 2
- Bacterial superinfection is common, making it difficult to determine which organism causes the nail damage 2
Chronic Paronychia with Candida
- Chronic paronychia occurs predominantly in patients with wet occupations or chronic moisture exposure, where swelling of the posterior nail fold develops secondary to water immersion 2
- The cuticle detaches from the nail plate, losing its water-tight properties, allowing microorganisms (both yeasts and bacteria) to enter the subcuticular space and cause further swelling 2
- Candida paronychia accounts for 5-10% of all onychomycosis cases and is more common in women than men, affecting fingernails more than toenails 2
- The most common Candida species implicated are C. albicans and C. parapsilosis 2
Trauma-Related Swelling
- Nail bed injuries from crush or avulsion mechanisms can cause significant swelling, particularly when both nail bed and nail fold are involved 3
- Artificial nails and nail polish can harbor microorganisms and trigger infection with associated swelling 4
Diagnostic Approach
Clinical Differentiation
- Acute paronychia presents with rapid onset of painful swelling after recent trauma, distinguishing it from chronic fungal infections that develop over weeks to months 5
- Unlike dermatophyte infections, pressure on and movement of the nail is painful in Candida paronychia 2
- Chronic paronychia shows less acute inflammation but persistent swelling with eventual proximal nail dystrophy 2
Laboratory Confirmation
- Culture of purulent material is recommended when an abscess is present to guide antibiotic therapy 5
- For suspected fungal involvement, direct microscopy with potassium hydroxide preparation and fungal culture on Saboraud's glucose agar should be performed 2, 6
- Treatment should not be instituted on clinical grounds alone, as 50% of nail dystrophy cases are fungal but cannot be accurately identified clinically 2
Treatment Algorithm
First-Line Conservative Management
- Warm water soaks for 10-15 minutes, 2-3 times daily, serve as first-line treatment for acute paronychia 5
- Dilute vinegar soaks (50:50 dilution with water) twice daily can be used as an alternative 5
- Apply mid-to-high potency topical corticosteroid ointment to nail folds twice daily to reduce inflammation 5
Candida-Specific Treatment
- For confirmed Candida paronychia, topical antifungal agents such as amorolfine 5% lacquer applied once or twice weekly for 6-12 months after filing diseased nail areas 2
- Amorolfine has been shown effective in approximately 50% of distal fingernail and toenail onychomycosis cases 2
- Broad-spectrum topical antifungal agents combined with corticosteroids are recommended for chronic paronychia 1
Bacterial Infection Management
- Topical antiseptic agents (octenidine) or topical antibiotics (nadifloxacin, gentamicin) for bacterial infections 7
- Pseudomonas infections (recognizable by green or black nail coloration) should be treated with ciprofloxacin 7
- For recurrent, severe, or treatment-refractory cases, consider doxycycline 100 mg twice daily with follow-up after 1 month 5
Surgical Intervention
- Surgical incision and drainage is indicated for more severe cases with abscess formation 1
- Herpetic whitlow may mimic an abscess but requires non-operative treatment to prevent sequelae 4
- En bloc excision of the proximal nail fold or eponychial marsupialization may be performed for recalcitrant chronic paronychia 1
Prevention and Patient Education
Occupational Considerations
- Hairdressers and others with chronic moisture exposure and chemical contact are at high risk for chronic paronychia if acute episodes don't fully resolve 5
- Patients should avoid excessive moisture exposure and wear protective gloves when working with chemicals 5, 6
Daily Preventive Measures
- Apply daily topical emollients to cuticles and periungual tissues to maintain barrier function 5, 6
- Application of emollient lotions is beneficial in preventing recurrence 1
- Protective nail lacquers can help prevent brittle nails and secondary infection 6
Common Pitfalls
- The most common cause of treatment failure is incorrect diagnosis made on clinical grounds alone 2
- Distinguishing between acute bacterial paronychia requiring drainage and viral herpetic whitlow requiring conservative management is critical 4
- Chronic paronychia is multifactorial (inflammatory reaction to irritants and allergens), not purely infectious, requiring combined anti-inflammatory and antimicrobial treatment 1
- Topical steroid creams are more effective than systemic antifungals in treating chronic paronychia 1