Chronic paronychia - Nail and Distal Digit
There is debate as to whether chronic paronychia is primarily an infectious or an inflammatory disease process; the current view is that chronic paronychia is a species of chronic irritant or allergic hand dermatitis. Evidence includes frequent association with occupational exposures in dishwashers, bartenders, laundry workers, nurses, swimmers, fishmongers, and cooks and a study demonstrating the superiority of treatment with potent topical steroids over systemic antifungals. Women are more frequently affected than men. It usually affects multiple fingernails.
Infectious pathogens also play a role in this condition. The chronic inflammatory process compromises the nail fold barrier to entry of microorganisms. Superinfection with bacteria may result in acute paronychia as a sequela. Fungal colonization and/or infection, especially with Candida albicans, is common. In one study, Candida was cultured in over 90% of patients with chronic paronychia.
Certain drugs can cause drug-induced paronychia (potentially either acute or chronic). These include retinoids (isotretinoin, acitretin), methotrexate, antiretroviral protease inhibitors (indinavir, lamivudine), and epidermal growth factor (EGF) receptor inhibitors (cetuximab, gefitinib, lapatinib). In some cases, drug-induced paronychia is associated with periungual lobular capillary hemangiomas (pyogenic granulomas).
Diabetes mellitus, immunosuppression, and inflammatory dermatoses are risk factors for developing chronic paronychia.
B37.2 – Candidiasis of skin and nail
200744008 – Chronic paronychia
Differential Diagnosis & Pitfalls
- Acute paronychia – may complicate chronic paronychia
- Herpetic whitlow – one or more blisters near the nail with honeycomb appearance
- Onychocryptosis (ingrown nail)
- Pemphigus vulgaris
- Lobular capillary hemangioma
- Pustular psoriasis
- Acrodermatitis continua of Hallopeau
- Reactive arthritis
- Digital mucous cyst – usually not inflamed
- Squamous cell carcinoma or squamous cell carcinoma in situ (Bowen disease)
- Periungual verruca vulgaris – usually with verrucous surface and not inflamed
- Atypical mycobacterial infection – associated with cleaning fish tanks
- Retronychia – look for associated retronychia (proximal ingrowing of nail plate into central surface of proximal nail fold) as a cause for chronic paronychia. It affects the great toenail most frequently. A history of trauma or microtrauma, and the presence of a yellowish nail should prompt further suspicion for this condition.