Paronychia

LAST UPDATED: May 28, 2022

Introduction

Paronychia is a soft tissue infection of the proximal or lateral nail folds, there are two main types - acute paronychia, a painful and purulent condition that is most frequently caused by Staphylococcus aureus, and chronic paronychia, which is most commonly seen in individuals involved in wet work, but can have a multifactorial aetiology. 

This chapter is set out as follows:


Clinical findings

Acute paronychia

  • Mainly affects children and adolescents
  • Acute paronychia presents as a tender swelling, most commonly of the lateral nail folds, with erythema and sometimes a pustule, which can occasionally evolve into an abscess 
  • The causative organisms are usually Staphylococcus aureus or streptococci, and, less commonly, pseudomonas or proteus species. Organisms enter through a break in the epidermis resulting from trauma to a nail fold, loss of the cuticle, or chronic irritation (eg, resulting from water and detergents). Biting or sucking fingers can also predispose to infection. In toes, infection often begins in an ingrown toenail
  • Occasionally the infection can be viral, due to either the herpes simplex virus (HSV), or orf virus. In cases of HSV infection (a herpetic whitlow), the presentation is that of vesicles, often grouped together. Such episodes can be recurrent

Chronic paronychia

  • Is an inflammatory dermatosis of the nail folds, which causes retraction of the periungual tissues with resultant secondary effects on the nail matrix, nail growth and soft‐tissue attachments. Although uncomfortable, chronic paronychia is generally less painful than acute paronychia
  • Causes
    • Chronic paronychia is predominantly a disease of domestic and catering workers, bar staff and fishmongers, where water and/or chemicals cause a contact irritant dermatitis. Handling of wet foods represents a particular hazard, as these often combine several predisposing factors including wet working conditions, a cold environment and irritation from the food itself
    • Other causes include an underling inflammatory dermatosis such as atopic eczema or psoriasis, and finger or thumb sucking in children 
    • Yeast infections, such as candida, can be associated as either a primary or secondary event. Dermatophytic paronychia is rare
  • Distribution 
    • Any finger may be involved, although it is most frequently the index and middle fingers of the right hand and the middle finger of the left
    • Toenails can also be affected 
  • Morphology
    • The condition begins as a slight erythematous swelling of the nail folds
    • The cuticle is lost and pus may collect beneath the nail fold
    • Repeated acute exacerbations impact on the nail matrix, which leads to the development of numerous irregular transverse nail ridges
    • The nail may become discoloured
    • In longstanding cases the nail may reduce in size

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Investigations

  • Swabs can be sent for C&S, and occasionally virology if HSV is suspected 

Management

Acute paronychia

  • The affected digit should be soaked in warm water several times daily
  • Topical antiseptics, eg Fucidin ® cream, may be used for localised, minor infection
  • An oral antistaphylococcal antibiotic may be necessary for more severe or prolonged bacterial infection
  • Surgical incision and drainage may be required for abscess formation
  • Consider early treatment with aciclovir in cases of HSV infection 

Chronic paronychia

  • Manage predisposing factors
    • Avoid any manipulation of the nail such as manicuring, or finger sucking 
    • Patients involved in wet work should be advised to wear rubber or plastic gloves, preferably with inner cotton gloves or cotton liners
    • Avoid the use of soaps and detergents, instead use a soap-substitute eg Dermol Wash ® Cutaneous Emulsion 
    • Emollient creams should be applied on a regular basis
  • Topical treatments
    • ​Lotions / drops (likely to penetrate better) eg clotrimazole 1% solution, or, gentamicin 1% combined with hydrocortisone acetate 1% drops
    • Trimovate ® cream applied BD can be useful during a flare-up as it combines a topical steroid with antiseptic and antifungal therapies. Other options include Daktacort ® cream, which contains a weaker steroid than ​Trimovate ® cream, or, occasionally a more potent topical steroid may be required for a short duration if the inflammation is more marked
  • Systemic treatments
    • In more troublesome cases, where a swab confirms Candida albicans then a short course of an oral antifungal therapy, such as itraconazole or fluconazole, may be required 

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