Whitlow is a painful infection of the fingertip or nail cuticle, caused by either the herpes simplex virus (HSV) or staphylococcus bacteria:
Herpetic whitlow
A painful infection caused by the HSV that usually appears on the top of the finger or thumb. Symptoms include swelling, pain, blisters, sores, redness, and feeling generally unwell. It can be caused by HSV-1 or HSV-2, and is usually spread by contact with an infected area, such as a torn cuticle.
Staphylococcal whitlow
Also known as a felon, this is a closed-space infection that causes severe, throbbing pain, redness, and swelling. It usually occurs after an injury or untreated paronychia.
Whitlow is easily treated and usually resolves within 2–4 weeks without treatment. However, you should seek immediate medical care if you or your child experience any of the following:
Increased pain, swelling, warmth, or redness
Red streaks leading from the area
Pus draining from the area
Fever