| Introduction |
 Definition
- soft tissue infection of the proximal or lateral nail fold
- Epidemiology
- most common hand infection (one third of all hand infections)
- most commonly involve the thumb
- usually in children
- more common in women (3:1)
- Classification
- acute paronychia
- minor trauma from nail biting, thumb sucking, manicure
- chronic paronychia
- occupations with prolonged exposure to water and irritant acid/alkali chemicals e.g. dishwashers, florists, gardeners, housekeepers, swimmers, bartenders
- medical conditions
- diabetes
- psoriasis
- steroids
- retroviral drugs (indinavir and lamivudine)
- indinavir is most common cause of paronychia in HIV positive patients
- resolves when medication is discontinued
- Organism
- acute infection
- adults - usually caused by Staphylococcus aureus
- children - usually mixed oropharyngeal flora
- diabetics - mixed bacterial infection
- chronic infection
- Candida albicans (more common in diabetics)
- often unresponsive to antibiotics
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| Anatomy |
- Nail organ
- adds to stability of finger tip by acting as counterforce to finger pulp
- thermoregulation (glomus bodies of nail bed and nail matrix)
- allows "extended precision grip" (using opposed thumbnail and index fingernail to pluck out a splinter)
- Nail plate
- made of keratin, grows at 3mm/month, faster in summer
- fingernails grow faster than toenails (fingernails take 3-6 months to regrow, and toenails take 12-18 months)
- growing part is under proximal eponychium
- Perionychium
- comprises hyponychium, eponychium and paronychium
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| Presentation |
- Symptoms
- acute paronychia
- erythema
- swelling
- nail fold tenderness
- chronic paronychia
- recurrent bouts of low-grade inflammation (less severe than acute paronychia)
- Physical exam
- acute paronychia
- fluctuance
- nail plate discoloration (green discoloration suggests Pseudomonas)
- chronic paronychia
- nail plate hypertrophy (fungal infection)
- nail fold blunting and retraction after repeated bouts of inflammation
- prominent transverse ridges on nail plate
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| Differentials |
- Herpetic whitlow
- Felon
- Onychomycosis
- Psoriasis
- Glomus tumor
- Mucous cyst
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| Treatment |
- Acute paronychia
- nonoperative
- warm soaks, oral antibiotics and avoidance of nail biting
- indications
- swelling only, but no fluctuance
- medications
- operative
- I&D with partial or total nail bed removal followed by oral abx
- indications
- fluctuance (indicates abscess collection)
- nail bed mobility (indicates tracking under the nail)
- obtain gram stain and culture
- perform in emergency room
- follow with oral antibiotics and routine dressing change
- Chronic paronychia
- nonoperative
- warm soaks, avoidance of finger sucking, topical antifungals
- indications
- medications
- miconazole is commonly used
- operative
- marsupialization (excision of doral eponychium down to level of germinal matrix)
- indications
- severe cases that fail nonoperative treatment
- technique
- combine with nail plate removal
- leave to heal by secondary intention
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| Techniques |
- I&D with partial or total nail bed removal
- approach
- incision into sulcus between lateral nail plate and lateral nail fold
- technique
- preserve eponychial fold by placing materials (removed nail) between skin and nail bed
- if abscess extends proximally over eponychium (eponychia), a separate counterincision is needed over the eponychium
- obtain gram stain and culture
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| Complications |
- Eponychia
- Runaround infection
- involvement of both lateral nail folds
- Felon
- spread volarward to pulp space
- I&D of finger pulp is necessary
- Flexor tenosynovitis
- volar spread into flexor sheath
- Subungual abscess ("floating nail")
- nail plate removal is necessary
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