Paronychia: Types, Diagnosis, Differential Diagnosis, and Treatment

Conclusions

• Acute paronychia is usually an infection of a single nail fold caused by minor trauma and common skin bacteria, and it is often managed conservatively unless abscess or cellulitis develops.
• Herpetic whitlow can closely mimic acute paronychia, so HSV should be considered when the presentation is very painful or vesicular.
• Painless or atypical paronychia should raise concern for uncommon causes such as tuberculosis, which may require biopsy and culture for diagnosis.
• Chronic paronychia is primarily an irritant or allergic dermatitis related to repeated wet work and exposure to soaps, solvents, or allergens rather than a primary infection.
• Avoiding irritants and using topical or intralesional corticosteroids are key treatments for chronic paronychia, while severe fibrotic cases may require surgical nail-fold excision.
• Paronychia can be a manifestation of other diseases, including psoriasis, pemphigus, retronychia, congenital malalignment, and nutritional deficiency such as zinc deficiency.
• Nail-unit squamous cell carcinoma can masquerade as chronic paronychia or onycholysis, so persistent or unusual nail-fold inflammation warrants suspicion for malignancy.
• Cancer therapies, especially taxanes and EGFR-targeted drugs, commonly cause painful paronychia, and severity can be tracked with tools such as the SPOT scoring system.
• Overall, accurate diagnosis of the underlying cause is crucial because paronychia is a clinical pattern with many infectious, inflammatory, metabolic, and neoplastic mimics.