A 45-year-old generally healthy female presents with 2 days of pain, swelling, redness, and a sensation of tightness around the right index fingertip. She admits to biting her nails often, and notes that her symptoms seemed to develop after she “went after a hangnail pretty aggressively” last week.
Exam reveals a tender, fluctuant collection at the medial nail fold of the right index finger. What’s your diagnosis, and how will you help her?
This is a paronychia, or an infection of the paronychial fold (review your nailbed anatomy). The pathogens at play in paronychiae are S. aureus (most commonly), S. pyogenes, Pseudomonas pyocyanea, and P. vulgaris.
Leave it untreated and you risk progression to cellulitis (as the infection extends) or even a chronic paronychia.
There are 3 main ways to drain a paronychia, so pick the one that works best for you and the individual patient in front of you. The goal is to create an outlet for the pus inside to leak out, so repeat the steps in whichever method you choose with that goal in mind.
A 10-minute warm water soak followed by lifting of the paronychial skin using an instrument with a flat, blunt edge (i.e. forceps, an 18-gauge needle, or the non-cutting edge of a scalpel)
A digital block followed by lifting of the paronychial skin, as well as the eponychial skin as needed (use the same method as listed above)
A digital block followed by direct incision and drainage of the collection
Post-procedure management and discharge instructions are key in cases such as this.
Educate your patient that paronychiae are most commonly caused by nail trauma… in other words, nail-biting and overzealous manicurists.
Instruct your patient that he/she needs to stop nail-biting, and have future manicurists push cuticles back instead of cutting them.
Show him/her how to separate the paronychial skin from the nail so he/she can continue management option 1 (above) several times per day until all symptoms have resolved.
Provide return precautions specifically for signs of cellulitis and systemic infection, and stress that the finger should be reassessed (by either an ED or the patient’s primary care physician within 48 hours.
Lastly, a common question: are post-drainage antibiotics required? Not necessarily, but you may consider them in cases where there is an associated cellulitis or your patient is infection-prone (think about diabetes, steroid use, immunosuppression, etc).
Take Away #1:
The infection has to have started beside the nail to be a paronychia. Understanding the anatomy of the finger and nailbed will help you differentiate, for example, between a felon and a paronychia.
Take Away #2:
Paronychiae are caused by nail trauma. Educate your patient that he/she must stop nail-biting and cuticle-cutting.
Take Away #3:
Treat a paronychia by soaking the digit in warm water, doing a digital block, and then gently separating the paronychial (plus perhaps the eponychial skin) from the nail using an instrument with a flat, blunt edge (i.e. forceps, an 18-gauge needle, or the non-cutting edge of a scalpel).
Edited by Bassam Zahid, MD