Paronychia

Management Strategy

Acute paronychia requires urgent effective treatment to prevent damage to the nail matrix. If the infection is superficial and pointing, then incision and drainage may be appropriate. Infection is often due to S. aureus, but β-hemolytic streptococci and anaerobic organisms may also be found. A swab should be taken for bacterial culture and antibiotic sensitivity and a broad-spectrum antibiotic covering both aerobic and anaerobic organisms given. Warm compresses with an astringent (e.g., aluminum acetate solution, if available) can help reduce edema and provide a hostile environment for bacteria. For deeper infections, if there has been no marked clinical improvement after 48 hours of antibiotic therapy, surgical treatment may be undertaken. Under local anesthesia, the proximal third of the nail plate is removed, and a gauze wick is laid under the proximal nailfold to allow drainage. Cases of antibiotic-resistant acute paronychia may be due to herpetic viruses, fungi, or non-infectious causes.

Chronic paronychia is usually due to dermatitis and often associated with wet work (e.g., in domestic workers, cooks, bartenders, fishmongers, etc.) and may be exacerbated by contact irritants or allergens. Immediate sensitivity to fresh foods can be a factor. In children, thumb sucking may initiate the condition. Eczema or psoriasis may predispose to chronic paronychia, as may poor peripheral circulation and rarely pemphigus vulgaris. Microtrauma, including overzealous manicuring of the cuticle, is also important. The middle and index fingers of the right hand and the middle finger of the left hand are most commonly affected, but any finger may be involved. Inflammation with bolstering of the nailfold and loss of the cuticle opens a space between the nailfold and the nail plate, which commonly becomes colonized with yeast, especially Candida species, and a wide range of other microorganisms. Acute exacerbations due to bacterial infection may occur.

Successful treatment relies on protection of the affected fingers from water, irritants, allergens, and trauma, together with antiinflammatory treatment using moderately potent or potent topical corticosteroids . Tacrolimus 0.1% ointment applied twice daily may also be effective. Swabs for yeast and bacteria should be taken, anticandidal preparations can be useful, and antibiotic preparations may also be needed. Treatment should be continued until the inflammation has subsided and the cuticle reformed and reattached to the nail plate (3 months or more). For repeated acute episodes, intralesional or systemic corticosteroids plus systemic antibiotics for a week may be useful. In cases where conservative management fails, surgery or low-dose superficial radiotherapy has been tried. For cases due to retronychia, simple avulsion of the nail plate is normally curative but conservative treatment using taping can be tried.

Drug-induced pseudopyogenic granulomatous paronychia responds to daily topical 2% mupirocin with clobetasol propionate ointment. Additionally, for patients on EGF or mTOR inhibitors, oral doxycycline 100 mg twice daily or dose reduction may be useful.