Snapshot A 25-year-old woman presents to the nail clinic for a painful middle finger. She obtains regular manicures, changing colors every 2 weeks. She recently had one a week ago and started feeling pain near the nail on her left middle finger. Her current medications include isotretinoin for treatment of acne. Physical exam reveals an erythematous proximal nail fold of the middle finger. When applying pressure to the nail plate, some pus drains from the nail. She is prescribed frequent warm soaks with chlorhexidine and oral antibiotics. Introduction Clinical definition inflammation of skin around the nail acute paronychia duration less than 6 weeks caused by bacterial infection chronic paronychia duration 6 weeks or more caused by chronic exposure to irritant or allergens Epidemiology Incidence very common Risk factors for acute paronychia nail biting finger sucking manicures pedicures ingrown nails for chronic paronychia occupations such as a dishwasher, barber, and healthcare professionals for both diabetes immunosuppression drugs retinoids antiretroviral therapy Etiology Acute paronychia Staphylococcus aureus γ-hemolytic streptococci Eikenella corrodens group A β-hemolytic streptococci Candida Chronic paronychia repeated exposure to environmental irritants a type of hand dermatitis, not a type of infection Pathogenesis acute paronychia active infection following minor trauma to nail bed or cuticles chronic paronychia nail plate separation from cuticle with inflammation can have subsequent yeast or bacterial colonization Presentation Symptoms pain Physical exam swelling and erythema of the proximal or lateral nail folds tender to palpation retraction of proximal nail fold pus under nail fold abscess digital pressure test blanch the nail to look for demarcation of abscess acute paronychia typically a single digit chronic paronychia typically several fingernails, most commonly the thumb, second, or third finger thickening or discoloration of nail Studies Diagnosis is usually based on clinical history and physical exam Differential Trauma Herpetic whitlow positive Tzanck test Psoriasis Felon abscess of the pulp space treatment incision and drainage antibiotics Treatment Conservative warm soaks indication symptomatic relief modalities aluminum acetate vinegar dilute povidone-iodine chlorhexidine Medical topical antibiotics indication acute paronychia minimal erythema and no abscess added to warm soaks drugs gentamicin mupirocin oral antibiotics indication persistent acute paronychia drugs trimethoprim-sulfamethoxazole clindamycin topical steroids indication chronic paronychia drugs betamethasone Operative incision and drainage indication if an abscess is present Complications Permanent nail plate dystrophy Prognosis Acute paronychia typically responsive to treatment Chronic paronychia is responsive to treatment, though responds very slowly resolves in weeks or even months