Beside the Nail, or In the Pad? They’re Different Infections With Different Deadlines.
Two finger infections account for most of what walks into a clinic, and people routinely mix them up.
- Paronychia sits at the edge of the nail. Red, swollen, sore along the nail fold, sometimes with a bead of pus you can see under the skin.
- A felon sits in the pulp of the fingertip, the fleshy pad you tap a screen with. Tense, throbbing, and out of all proportion to how it looks.
The distinction matters because a paronychia often settles with soaks and time, and a felon almost never does. A felon left alone eats into the bone underneath.
Paronychia: the one at the nail fold
It starts with a breach in the seal between nail and skin. A hangnail pulled off. Nail biting. An aggressive manicure. A picked cuticle.
Bacteria get in, and within a day or two the fold beside the nail is red, puffy and tender.
The question that decides treatment: is there pus collected, or is it just inflamed?
So what you do?
Press gently along the fold. A soft, boggy area with a visible yellow-white collection under the skin is an abscess, and abscesses do not resolve with antibiotics alone. They need draining, which is a small procedure and gives near-immediate relief.
If it’s firm, red and tender with no visible collection, early treatment is genuinely simple: warm soaks several times a day, keep the finger out of water otherwise, don’t pick at it, and see someone if it isn’t clearly better in 2 to 3 days or if it’s spreading.
(Do not try to drain it yourself with a needle from the kitchen drawer. I’ve seen what that turns into, and the thing it turns into is the article I wrote about tendon sheath infections.)
The chronic version is a different animal
If the nail fold has been mildly swollen, boggy and unhappy for months rather than days, often across several fingers, that’s chronic paronychia and it’s usually not a straightforward bacterial infection. It belongs to people whose hands are wet all day: chefs, cleaners, bar staff, nurses, parents of small children.
Antibiotics generally don’t fix it. Keeping hands dry, gloves for wet work, and treatment aimed at yeast rather than bacteria is the usual direction. It takes months and it comes back if the wet work doesn’t change.
Felon: the one in the fingertip pad
This one deserves more respect than it gets, because of how the fingertip is built.
The pulp of your fingertip isn’t a simple bag of fat. It’s divided into many small compartments by fibrous walls running from the bone to the skin, which is what gives your fingertip its firm, stable feel when you pinch.
Get an infection inside those compartments and the pus has nowhere to expand. Pressure builds fast in a closed space, which does two things: it produces pain far worse than the appearance suggests, and it squeezes shut the small vessels feeding the tissue and the bone.
A paronychia hurts. A felon throbs so hard it keeps you awake and you can feel your pulse in it. That difference is pressure, and pressure is the reason it needs draining rather than waiting.
Signs:
- the whole pad of the fingertip is swollen and tense,
- shiny,
- hot,
- and exquisitely painful to any touch.
The rest of the finger is usually normal, which is what separates it from a tendon sheath infection.
Left untreated it can progress to infection of the bone in the fingertip, death of the skin over the pad, or spread into the tendon sheath. This isn’t a “maybe” – it’s a chance of it happening, and all three are common enough that hand surgeons drain felons promptly rather than trying antibiotics first.
When either becomes an emergency
Go the same day, not in a few days, if:
- Redness is spreading up the finger or into the hand, or you can see a red line tracking up the arm.
- You feel unwell, feverish or shivery.
- The whole finger is swelling, not just one part, and it hurts badly to straighten. That’s the tendon sheath, and it’s an emergency.
- You’re diabetic, immunosuppressed, or on chemotherapy. Your threshold to be seen should be far lower, and the usual signs may be muted.
- The infection followed a bite, human or animal. Bites to the hand behave differently and badly.
Recovery, and the part nobody mentions
After a paronychia is drained: relief is immediate, dressings for a few days, and the finger is usually back to normal within a week or two. If the nail was involved, a ridge or a temporary nail deformity can grow out over the following months.
After a felon is drained: expect a couple of weeks of dressings and a fingertip that stays sensitive for considerably longer.
That’s the part people aren’t warned about.
The fingertip is one of the most densely innervated pieces of skin on your body. After an infection and an incision through it, the pad can stay hypersensitive, oddly numb in patches, or both, for months. Pinching, typing and buttons can be genuinely uncomfortable well after the wound has healed.
This responds well to desensitisation work: graded textures against the pad, several short sessions a day, deliberately using the finger rather than protecting it. Protecting a sensitive fingertip is the reliable way to keep it sensitive.
The short version
Beside the nail: paronychia. Soaks and watching if it’s early and there’s no pus collected, drainage if there is.
In the pad, tense and throbbing: felon. Get it seen and drained, because the fingertip’s own architecture is what makes waiting expensive.
And whole finger swollen with pain on straightening is neither of these. That one goes to hospital tonight.
Written by Nigel Chua, hand occupational therapist in practice since 2005. Tens of thousands of hands, wrists and elbows assessed and treated. My credentials are here. This article explains; it doesn’t examine. Spreading redness, fever, or a finger infection in someone with diabetes needs seeing the same day.