What are the diagnostic tests and treatment options for paronychia?

Diagnostic Testing and Treatment of Paronychia

Paronychia is primarily a clinical diagnosis that requires culture of purulent material when an abscess is present to guide antibiotic therapy, with treatment centered on warm water or dilute vinegar soaks, topical corticosteroids, and drainage when indicated. 1

Diagnostic Approach

Clinical Diagnosis

• Paronychia is diagnosed clinically based on erythema, swelling, tenderness, and pain of the lateral or proximal nail folds 2, 3
• The thumbs and great toes are most frequently affected, likely due to repeated trauma 2

When to Obtain Cultures

• Culture purulent material when an abscess is present to identify bacterial, viral, or fungal pathogens and guide antibiotic selection 1, 2
• Obtain bacterial/viral/fungal cultures if infection is suspected, particularly in antibiotic-resistant cases 2, 4
• Up to 25% of cases have secondary bacterial or mycological superinfection 2
• Both gram-positive and gram-negative organisms can be implicated 2

Distinguishing Acute from Chronic Paronychia

• Acute paronychia develops rapidly after trauma or barrier breach, with symptoms lasting less than 6 weeks 3
• Chronic paronychia is characterized by symptoms lasting at least 6 weeks and represents an irritant contact dermatitis rather than primarily infectious process 3, 2
• Chronic paronychia commonly affects individuals with wet occupations (housekeepers, dishwashers, bartenders, florists, bakers, swimmers) 3, 2

Key Differential Diagnosis

• Onychomycosis presents with nail thickening, discoloration, and friable texture developing over weeks to months—not acute swelling after recent trauma 1
• Consider non-infectious causes in antibiotic-resistant cases: viral infections (36%), drug-induced (5%), pemphigus vulgaris (5%), or trauma (2%) 4
• Cytologic examination with Tzanck smear may be diagnostically useful in antibiotic-resistant cases 4

Treatment Algorithm

First-Line Treatment for Acute Paronychia

Conservative Management:

• Warm water soaks for 10-15 minutes, 2-3 times daily as first-line treatment 1, 3
• Dilute vinegar soaks (50:50 dilution with water) twice daily as an alternative 1, 2
• Mid-to-high potency topical corticosteroid ointment to nail folds twice daily to reduce inflammation 1, 2, 3
• Topical antibiotics may be added when simple soaks do not relieve inflammation 3

When Abscess is Present

• Surgical drainage is mandatory when an abscess is identified 3, 5
• Drainage options range from instrumentation with a hypodermic needle to wide incision with scalpel 3
• For paronychia with abscess, an intra-sulcal approach is preferable to a nail fold incision 5
• Oral antibiotics are usually not needed if adequate drainage is achieved, unless the patient is immunocompromised or severe infection is present 3

Escalation for Severe or Refractory Cases

• Doxycycline 100 mg twice daily for recurrent, severe, or treatment-refractory cases, with follow-up after 1 month 1, 2
• For granulation tissue: scoop shave removal with hyfrecation or silver nitrate application 2
• Topical timolol 0.5% gel twice daily under occlusion showed complete clearance of periungual pyogenic granulomas in cancer patients treated with EGFRis 2
• Intralesional triamcinolone acetonide for recurrent or severe cases 2

Management of Associated Onychocryptosis (Ingrown Nail)

• Dental floss nail splinting: insertion under the ingrown nail separates the lateral nail edge from underlying tissue 2
• Cotton packing or cast edge separation 2
• Flexible tube splinting with acrylic treatment and gutter splint 2
• Taping nail fold away from nail plate 2, 1

Chronic Paronychia Treatment

• Stop the source of irritation (moisture, chemicals, allergens) 3
• Topical steroids or calcineurin inhibitors to treat the underlying irritant dermatitis 3
• Treatment may take weeks to months 3
• Consider dermatology consultation for suspected chronic paronychia 5
• For chronic cases with proven Candida colonization, oral fluconazole 100 mg for 20 days may be added 6

Critical Prevention Measures

Patient education is paramount to prevent recurrence: 1, 2

• Avoid excessive moisture exposure and wear protective gloves when working with chemicals 1, 3
• Apply daily topical emollients to cuticles and periungual tissues 1, 2
• Avoid nail-biting, finger-sucking, or cutting nails too short 2, 4
• Regular trimming of nails ensuring they are straight and not too short 2
• Wear comfortable well-fitting shoes and cotton socks 2
• Gentle skin care and avoidance of repeated friction/trauma 2

Common Pitfalls

• Do not treat paronychia on clinical grounds alone without considering culture when pus is present, as antibiotic-resistant cases may have viral, fungal, or non-infectious etiologies 4
• Do not prescribe oral antibiotics routinely—they are unnecessary if adequate drainage is achieved in immunocompetent patients 3
• Do not confuse acute paronychia with onychomycosis, which develops over weeks to months with characteristic nail plate changes 1
• In occupational chronic paronychia, treatment will fail without addressing the underlying irritant exposure 3, 6
• Investigate for unusual causes (malignancy, pemphigus vulgaris) in chronic paronychia unresponsive to standard treatment 5, 7