Paronychia

Introduction

Paronychia is an infection or inflammation of the periungual tissues, the skin surrounding the nail, which can be acute or chronic. Acute paronychia usually develops rapidly, often as a result of trauma to the nail fold, while chronic paronychia occurs over time due to repeated exposure to irritants or allergens. The condition can cause significant pain and swelling and may lead to abscess formation or, in chronic cases, nail dystrophy.

Aetiology and Risk Factors

The causes of paronychia differ based on whether it is acute or chronic:

Acute Paronychia

• Bacterial Infection: The most common cause of acute paronychia is a bacterial infection, particularly by Staphylococcus aureus or Streptococcus species. The infection typically enters through a break in the skin around the nail, such as from nail biting, picking at hangnails, or manicures.
• Trauma: Trauma to the nail fold, such as from aggressive nail care, can predispose to acute paronychia by creating an entry point for pathogens.

Chronic Paronychia

• Repeated Irritation: Chronic paronychia is often caused by repeated exposure to water, detergents, and other irritants, which can damage the cuticle and allow for infection. This condition is common among individuals who frequently have their hands in water, such as cleaners, bartenders, and healthcare workers.
• Fungal Infection: Chronic cases are frequently associated with fungal infections, particularly by Candida albicans, though bacteria may also be involved.
• Underlying Conditions: Conditions like eczema, diabetes, or immunosuppression can increase the risk of chronic paronychia.

Clinical Presentation

Paronychia presents with different symptoms depending on whether it is acute or chronic:

Acute Paronychia

• Rapid Onset: Symptoms typically develop quickly, within a few hours to a couple of days.
• Pain and Tenderness: There is often severe pain and tenderness around the affected nail, with swelling and redness of the periungual area.
• Pus Formation: An abscess may develop, leading to the accumulation of pus under the skin around the nail.
• Nail Discolouration: The nail may appear discoloured, and in severe cases, the nail may become partially detached from the nail bed.

Chronic Paronychia

• Gradual Onset: Symptoms develop slowly over weeks to months.
• Mild Discomfort: The pain is usually less severe than in acute paronychia, but there may be persistent tenderness and swelling.
• Nail Changes: Chronic paronychia can lead to thickening of the nail, ridging, and discolouration. The cuticle is often lost, and the nail fold may appear red and swollen.
• Recurrent Episodes: The condition often recurs, especially if the underlying irritant or infection is not addressed.

Diagnosis

The diagnosis of paronychia is primarily clinical, based on the characteristic appearance of the affected nail and surrounding tissues:

• Clinical Examination: The key to diagnosis is the physical examination of the nail and periungual area, noting the presence of swelling, erythema, tenderness, and any pus or discharge.
• Culture and Sensitivity: If pus is present, a swab can be taken for bacterial culture and sensitivity testing to identify the causative organism and guide antibiotic therapy.
• Fungal Culture: In cases of chronic paronychia, a fungal culture may be warranted to identify Candida or other fungal pathogens.
• Imaging: In cases of suspected osteomyelitis (infection of the bone), particularly if the infection is recurrent or does not respond to initial treatment, imaging such as X-rays may be considered.

Management and Treatment

Treatment of paronychia depends on whether the condition is acute or chronic, and on the severity of the symptoms:

1. Acute Paronychia

• Warm Soaks: Soaking the affected finger or toe in warm water for 15-20 minutes several times a day can help reduce pain and swelling and promote drainage of any pus.
• Incision and Drainage: If an abscess has formed, it may need to be incised and drained by a healthcare professional to relieve pressure and clear the infection. This procedure is typically done under local anaesthesia.
• Antibiotics: Oral antibiotics such as flucloxacillin or erythromycin may be prescribed, especially if there is significant cellulitis or if the patient is immunocompromised. In cases of suspected MRSA, doxycycline or trimethoprim-sulfamethoxazole may be used.
• Pain Management: Over-the-counter analgesics such as paracetamol or ibuprofen can help manage pain.

2. Chronic Paronychia

• Avoidance of Irritants: Patients should be advised to keep the affected area dry and avoid exposure to water, detergents, and other irritants. Wearing gloves during activities that involve water or chemicals can help prevent recurrence.
• Topical Antifungals: Antifungal creams such as clotrimazole or miconazole can be applied to the affected area if a fungal infection is suspected or confirmed.
• Topical Steroids: Mild topical corticosteroids may be used to reduce inflammation, particularly in cases where irritation and inflammation are prominent features.
• Oral Antifungals: In persistent or severe cases, oral antifungal therapy with agents such as fluconazole may be necessary.
• Nail Care: Proper nail care, including avoiding aggressive manicures and keeping the nails clean and trimmed, can help prevent the condition from worsening.

When to Refer

Referral to a specialist may be necessary in the following situations:

• Recurrent or Severe Cases: If the paronychia is recurrent, severe, or unresponsive to standard treatment, referral to a dermatologist or hand specialist is recommended.
• Suspected Osteomyelitis: If there is a concern for underlying bone infection, particularly in cases of chronic or severe acute paronychia, specialist evaluation is necessary.
• Immunocompromised Patients: Patients with underlying conditions that compromise the immune system may require more aggressive treatment and specialist input.

References

1. British Association of Dermatologists (2024) Guidelines for the Management of Paronychia. Available at: https://www.bad.org.uk (Accessed: 26 August 2024).
2. National Institute for Health and Care Excellence (2024) Paronychia: Diagnosis and Treatment. Available at: https://www.nice.org.uk/guidance/ng199 (Accessed: 26 August 2024).
3. British National Formulary (2024) Topical and Systemic Treatments for Skin Infections. Available at: https://bnf.nice.org.uk/ (Accessed: 26 August 2024).