Paronychia is inflammation of the skin around a finger or toenail. It can be acute or chronic.
Paronychia is also called whitlow. It may be associated with felon (infection of the pulp of the fingertip).
Who gets paronychia?
Acute paronychia can affect anyone. However, it is more likely to follow a break in the skin, especially between the proximal nail fold/cuticle and the nail plate. For example:
- If the nail is bitten (onychophagia) or the nail-fold is habitually picked
- In infants that suck their fingers or thumbs
- Following manicuring
- Ingrown toenails (onychocryptosis)
- On application of sculptured or artificial fingernails
- Treatment with oral retinoid that dries the skin (acitretin, isotretinoin)
- Other drugs, including epidermal growth factor receptor and BRAF inhibitors (vemurafenib, dabrafenib)
Chronic paronychia mainly occurs in people with hand dermatitis, or who have constantly cold and wet hands, such as:
Acute and chronic skin infections tend to be more frequent and aggressive in patients with diabetes or chronic debility, or that are immune suppressed by drugs or disease.
What causes paronychia?
The cause or causes of chronic paronychia are not fully understood. In many cases, it is due to dermatitis of the nail fold. Often several different micro-organisms can be cultured, particularly Candida albicans and the Gram negative bacilli, pseudomonas.
What are the clinical features of paronychia?
Acute paronychia develops rapidly over a few hours, and usually affects a single nail fold. This becomes painful, red and swollen. If herpes simplex is the cause, multiple tender vesicles may be observed. Sometimes yellow pus appears under the cuticle and can evolve to abscess. The nail plate may lift up. Acute paronychia due to Streptococcus pyogenes may be accompanied by fever, lymphangiitis and tender lymphadenopathy.
Chronic paronychia is a gradual process. It may start in one nail fold but often spreads to several others. Each affected nail fold is swollen and lifted off the nail plate. The affected skin may be red and tender from time to time, and sometimes a little pus (white, yellow or green) can be expressed from under the cuticle.
What are the complications of paronychia?
Acute paronychia can spread to cause a serious hand infection (cellulitis) and may involve underlying tendons (infectious tendonitis).
The main complication of chronic paronychia is nail dystrophy. It is often associated with distorted, ridged nail plates. They may become yellow or green/black and brittle. After recovery, it takes up to a year for the nails to grow back to normal.
How is paronychia diagnosed?
What is the treatment for paronychia?
- Soak affected digit in warm water, several times daily.
- Topical antiseptic may be prescribed for localised, minor infection.
- Oral antibiotics may be necessary for severe or prolonged bacterial infection.
- Consider early treatment with aciclovir in case of severe herpes simplex infection.
- Surgical incision and drainage may be required for abscess followed by irrigation and packing with gauze.
- Rarely, the nail must be removed to allow pus to drain.
Attend to predisposing factors.
- Keep the hands dry and warm.
- Avoid wet work, or use totally waterproof gloves.
- Keep fingernails scrupulously clean.
- Wash after dirty work with soap and water, rinse off and dry carefully.
- Apply emollient hand cream frequently – dimeticone barrier creams may help.
Treatment should focus on the dermatitis and any microbes grown on culture.
- Topical corticosteroid ointment for 2–4 weeks and for flares
- Antiseptics or antifungal lotions or solutions for several months
- Oral antifungal agent (itraconazole or fluconazole), if C albicans confirmed
What is the outlook for paronychia?
Acute paronychia usually clears completely in a few days, and rarely recurs in healthy individuals.
Chronic paronychia may persist for months or longer, and can recur in predisposed individuals.