Summary Paronychias are soft tissue infections of the proximal or lateral nail fold. Diagnosis involves careful clinical examination assessing for erythema and fluctuance around the nail with discoloration/hypertrophic changes of the nail. Treatment involves warm soaks and oral antibiotics and if fluctuance is present, debridement and partial/complete nail removal is warranted. Epidemiology Incidence most common hand infection (one third of all hand infections) Demographics usually in children more common in women (3:1) Anatomic location most commonly involve the thumb Etiology Pathophysiology 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 Classification Acute paronychia minor trauma from nail biting, thumb sucking, manicure Chronic paronychia occupations with prolonged exposure to water and irritant acid/alkali chemicalse.g. dishwashers, florists, gardeners, housekeepers, swimmers, bartenders risk factors for chronic paronychia diabetes psoriasis steroids retroviral drugs (indinavir and lamivudine) indinavir is most common cause of paronychia in HIV positive patients resolves when medication is discontinued 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 Presentation Symptoms acute paronychia pain and nail fold tenderness erythema swelling 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 Differential Herpetic whitlow Felon Onychomycosis Psoriasis Glomus tumor Mucous cyst Treatment Acute paronychia nonoperative warm soaks, oral antibiotics and avoidance of nail biting indications swelling only, but no fluctuance medications augmentin or clindamycin 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) follow with oral antibiotics and routine dressing change Chronic paronychia nonoperative warm soaks, avoidance of finger sucking, topical antifungals indications first line of treatment medications miconazole is commonly used operative marsupialization (excision of dorsal 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 Techniques I&D with partial or total nail bed removal approach may be done in emergency room 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 Complications Eponychia spread into eponychium 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