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Emergency and Acute Medicine – Paronychia
Paronychia is an inflammatory condition of the nail folds surrounding the nail plate that occurs when disruption of the protective seal between the nail plate and nail fold allows microorganisms to enter the eponychial space. This disruption commonly follows minor trauma and leads to localized infection and inflammation.
The etiology differs between acute and chronic paronychia. Acute paronychia is most commonly caused by *Staphylococcus aureus*, although streptococci, *Pseudomonas*, and anaerobic organisms may also be involved. Chronic paronychia is multifactorial and results from repeated exposure to allergens and irritants, with fungal organisms—most commonly *Candida albicans*—frequently coexisting alongside *Staphylococcus* species.
Clinically, paronychia presents with pain, warmth, swelling, and erythema of the proximal or lateral nail folds, usually developing two to five days after trauma. For symptoms to meet criteria for chronic paronychia, they must persist for more than six weeks. A careful history is important. Acute paronychia is often associated with nail biting, finger sucking, aggressive manicuring, or direct trauma. Chronic paronychia is commonly seen in individuals with occupations involving persistent moisture exposure, such as dishwashers or bartenders, and occurs more frequently in patients with diabetes or peripheral vascular disease. In children, infections often involve anaerobic oral flora due to nail biting.
On physical examination, early paronychia begins as localized erythema, swelling, and tenderness at the dorsolateral nail fold, which may bulge over the nail plate. As the condition progresses, a subcuticular or subungual abscess may form. Green discoloration of the nail suggests *Pseudomonas* infection, while nail plate hypertrophy raises concern for a fungal etiology.
The diagnosis of paronychia is primarily clinical and based on history and physical examination. Evaluation should include assessment for associated infections such as felon or cellulitis and confirmation of tetanus immunization status. Laboratory testing is generally not helpful, and cultures are not routinely indicated. If herpetic whitlow is suspected, a Tzanck smear or viral culture may be considered. Imaging with soft tissue radiographs is reserved for suspected foreign bodies or possible osteomyelitis. A digital pressure test, using opposing pressure between the thumb and affected finger, may help identify early subungual abscess formation.
Management depends on the stage and type of paronychia. Early acute paronychia without purulence can often be treated with warm-water soaks four times daily, with or without topical antibiotics or corticosteroids. If a superficial abscess is present, elevation of the eponychial fold using a small blade or needle may allow adequate drainage; local anesthesia or a digital nerve block may be required. When infection extends beneath the nail plate, partial nail removal may be necessary, while extensive subungual abscesses may require complete nail removal. Runaround abscesses involving both sides of the nail fold require partial proximal nail removal with packing to prevent re-adhesion.
Antibiotic therapy is recommended when there is cellulitis, abscess formation, or systemic signs of infection. Appropriate first-line oral agents include trimethoprim–sulfamethoxazole, dicloxacillin, or amoxicillin–clavulanate, typically for five to ten days depending on severity. Clindamycin or amoxicillin–clavulanate is preferred when infection is associated with nail biting or oral exposure. Chronic paronychia management focuses on avoidance of irritants and moisture, with topical corticosteroids considered first-line therapy, often combined with a broad-spectrum topical antifungal. Refractory cases may require surgical eponychial marsupialization or oral antifungal therapy.
Admission is rarely required for paronychia alone. Patients with uncomplicated infections may be discharged with appropriate wound care instructions and follow-up. Those with packing in place should be re-evaluated within 24 hours. Referral is indicated for chronic or recurrent paronychia that does not respond to standard therapy.
Key clinical pearls include recognizing that acute paronychia generally responds well to timely drainage with or without antibiotics, while chronic paronychia is usually driven by repeated exposure to irritants rather than infection alone. Conditions such as psoriasis, Reiter syndrome, and herpetic whitlow can mimic paronychia and should be considered in recurrent or atypical cases.
Paronychia is an inflammatory condition of the nail folds surrounding the nail plate that occurs when disruption of the protective seal between the nail plate and nail fold allows microorganisms to enter the eponychial space. This disruption commonly follows minor trauma and leads to localized infection and inflammation.
The etiology differs between acute and chronic paronychia. Acute paronychia is most commonly caused by *Staphylococcus aureus*, although streptococci, *Pseudomonas*, and anaerobic organisms may also be involved. Chronic paronychia is multifactorial and results from repeated exposure to allergens and irritants, with fungal organisms—most commonly *Candida albicans*—frequently coexisting alongside *Staphylococcus* species.
Clinically, paronychia presents with pain, warmth, swelling, and erythema of the proximal or lateral nail folds, usually developing two to five days after trauma. For symptoms to meet criteria for chronic paronychia, they must persist for more than six weeks. A careful history is important. Acute paronychia is often associated with nail biting, finger sucking, aggressive manicuring, or direct trauma. Chronic paronychia is commonly seen in individuals with occupations involving persistent moisture exposure, such as dishwashers or bartenders, and occurs more frequently in patients with diabetes or peripheral vascular disease. In children, infections often involve anaerobic oral flora due to nail biting.
On physical examination, early paronychia begins as localized erythema, swelling, and tenderness at the dorsolateral nail fold, which may bulge over the nail plate. As the condition progresses, a subcuticular or subungual abscess may form. Green discoloration of the nail suggests *Pseudomonas* infection, while nail plate hypertrophy raises concern for a fungal etiology.
The diagnosis of paronychia is primarily clinical and based on history and physical examination. Evaluation should include assessment for associated infections such as felon or cellulitis and confirmation of tetanus immunization status. Laboratory testing is generally not helpful, and cultures are not routinely indicated. If herpetic whitlow is suspected, a Tzanck smear or viral culture may be considered. Imaging with soft tissue radiographs is reserved for suspected foreign bodies or possible osteomyelitis. A digital pressure test, using opposing pressure between the thumb and affected finger, may help identify early subungual abscess formation.
Management depends on the stage and type of paronychia. Early acute paronychia without purulence can often be treated with warm-water soaks four times daily, with or without topical antibiotics or corticosteroids. If a superficial abscess is present, elevation of the eponychial fold using a small blade or needle may allow adequate drainage; local anesthesia or a digital nerve block may be required. When infection extends beneath the nail plate, partial nail removal may be necessary, while extensive subungual abscesses may require complete nail removal. Runaround abscesses involving both sides of the nail fold require partial proximal nail removal with packing to prevent re-adhesion.
Antibiotic therapy is recommended when there is cellulitis, abscess formation, or systemic signs of infection. Appropriate first-line oral agents include trimethoprim–sulfamethoxazole, dicloxacillin, or amoxicillin–clavulanate, typically for five to ten days depending on severity. Clindamycin or amoxicillin–clavulanate is preferred when infection is associated with nail biting or oral exposure. Chronic paronychia management focuses on avoidance of irritants and moisture, with topical corticosteroids considered first-line therapy, often combined with a broad-spectrum topical antifungal. Refractory cases may require surgical eponychial marsupialization or oral antifungal therapy.
Admission is rarely required for paronychia alone. Patients with uncomplicated infections may be discharged with appropriate wound care instructions and follow-up. Those with packing in place should be re-evaluated within 24 hours. Referral is indicated for chronic or recurrent paronychia that does not respond to standard therapy.
Key clinical pearls include recognizing that acute paronychia generally responds well to timely drainage with or without antibiotics, while chronic paronychia is usually driven by repeated exposure to irritants rather than infection alone. Conditions such as psoriasis, Reiter syndrome, and herpetic whitlow can mimic paronychia and should be considered in recurrent or atypical cases.
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