What are the possible causes of nail plate discoloration following removal of acrylic nail enhancements?

Fingernail Discoloration After Acrylic Nail Removal

The most common causes of nail discoloration after acrylic nail removal are fungal infection (onychomycosis), bacterial colonization (especially Candida or Pseudomonas), allergic contact dermatitis to acrylate monomers, and mechanical trauma from the removal process itself. 1, 2

Primary Diagnostic Considerations

Infectious Causes

Fungal infection is extremely common after artificial nail use, with mycological studies showing positive cultures in 98.5% of patients with nail changes following acrylic nail removal 2. The key features to assess include:

• Candida species are the predominant pathogen in artificial nail-related infections, found in the majority of cases 2
• Look for soft, friable nail texture with thickening and discoloration, which strongly suggests fungal infection 1
• Green discoloration indicates Pseudomonas aeruginosa bacterial infection (Green Nail Syndrome), which requires keeping the area dry and applying topical povidone iodine 2% twice daily 1
• Fungal infections typically present with nail thickening, discoloration, and friable texture 1

Critical diagnostic step: Obtain mycological confirmation before treating presumed fungal infection, as 50% of dystrophic nails are non-fungal despite similar appearance 1, 3. Collect specimens from the distal nail plate and subungual debris for both KOH preparation and fungal culture 1.

Allergic Contact Dermatitis

Acrylate sensitization is a common adverse reaction to artificial nails, affecting more than one-third of exposed patients 4:

• The most frequent allergens are 2-hydroxyethyl methacrylate (2-HEMA) and 2-hydroxypropyl methacrylate (2-HPMA), each causing reactions in 17.5% of tested patients 4
• Ethyleneglycol dimethacrylate (EGDM) causes reactions in 13.4% of cases 4
• Clinical presentation includes chronic dermatitis of the hands and fingers, with paronychia, nail dystrophy, and onycholysis 4
• Severe onychodystrophy can develop within 1 week of acrylic nail application in sensitized individuals 5

Consider patch testing if inflammatory changes predominate over infectious features 3.

Mechanical and Chemical Trauma

"Worn-down nail syndrome" results from repetitive chemical or mechanical trauma during acrylic nail application and removal 6:

• Characterized by thinning of the distal nail plate from aggressive nail filing during removal 6
• The nail appears thin, fragile, and may show discoloration from the underlying nail bed showing through the thinned plate 6

Chronic Irritant Contact Paronychia

Moisture exposure during and after artificial nail wear can cause chronic paronychia with secondary nail changes 3:

• Horizontal ridges (Beau's lines) indicate nail matrix inflammation from chronic paronychia 3
• The cuticle seal is disrupted, allowing irritants and microorganisms to enter the sub-cuticular space 3
• This creates a cycle of inflammation affecting nail growth 3

Diagnostic Algorithm

1. Examine the nail texture and color pattern:

   • Soft, friable texture with yellow-brown discoloration → suspect fungal infection 1
   • Green discoloration → Pseudomonas infection 1
   • Thin, translucent nail plate → mechanical trauma from filing 6
   • Paronychia with nail fold swelling → Candida infection or chronic irritant dermatitis 1, 3

2. Obtain mycological specimens if fungal infection is suspected:

   • Scrape subungual debris from beneath the nail plate 1
   • Submit for both KOH preparation and fungal culture on Sabouraud's glucose agar 1
   • Sampling from the distal nail yields significantly better results than proximal nail fold sampling 2

3. Assess for inflammatory features:

   • Look for nail fold erythema, scaling, or eczematous changes suggesting allergic contact dermatitis 4
   • Check for involvement of periungual skin and distant sites (face, neck) which suggests acrylate allergy 4

Management Approach

For Confirmed or Suspected Fungal Infection

• Keep the nail area dry using a hair dryer, as moisture-loving organisms cannot survive in dry environments 7
• Treat confirmed fungal infections with systemic antifungal agents (terbinafine or itraconazole) only after mycological confirmation 1
• For Pseudomonas (green nail), apply topical povidone iodine 2% twice daily and maintain dryness 1

For Inflammatory/Allergic Causes

• Apply mid- to high-potency topical corticosteroid ointment to nail folds twice daily as first-line therapy 3
• This is more effective than antifungal agents for chronic paronychia 3
• Use daily topical emollients on cuticles and periungual tissues to restore the barrier 1, 3

For Mechanical Trauma

• Apply daily emollients to the nail plate and periungual folds 1
• Use protective nail lacquers to limit water loss 1
• Avoid further trauma and allow the nail to grow out naturally 1

Critical Pitfalls to Avoid

• Do not prescribe empirical antifungal therapy without mycological confirmation, as about 50% of dystrophic nails are non-fungal and topical steroids are more effective for inflammatory causes 1, 3
• Do not assume Candida colonization is the primary cause of fingernail onycholysis—it is usually a secondary colonizer in the onycholytic space created by other mechanisms 7
• Do not overlook occupational or behavioral factors: patients need counseling on wearing cotton-lined waterproof gloves during wet work and avoiding repeated moisture exposure 1, 3
• Do not ignore the possibility of acrylate allergy, especially if inflammatory changes predominate or if the patient has occupational exposure to nail products 4