Herpetic whitlow
Herpetic whitlow is a painful herpes simplex virus infection of a finger or thumb, usually producing clustered blisters near the nail or fingertip.
Herpes simplex virus: A group of viruses that cause lifelong infections with episodes of active disease and latency. HSV-1 or HSV-2 infects the finger and can remain latent in sensory nerves.
Vesicle: A small, fluid-filled blister within or beneath the outer layer of skin. Whitlow commonly appears as grouped vesicles on a red, swollen finger.
Polymerase chain reaction: A laboratory method that amplifies selected DNA sequences for detection or analysis. PCR testing of blister fluid can identify HSV when the appearance is uncertain.
Felon: A bacterial infection of the fingertip pulp that causes a tense, painful abscess. A felon affects the fingertip pad and may require drainage, unlike typical whitlow.
Herpetic whitlow recurrence: A later episode of finger lesions caused by reactivation of latent herpes simplex virus. Reactivation can bring back painful blisters after the first whitlow episode has resolved.
Herpes simplex virus latency: The persistence of herpes simplex viral genetic material in host cells between episodes of active replication. Latency in sensory nerve cells explains why whitlow can recur at the same site.
Paronychia: Inflammation or infection of the tissue surrounding a fingernail or toenail. Its nail-fold swelling can resemble whitlow, but bacterial paronychia often forms pus.
Acyclovir: An antiviral medication used to treat infections caused by herpesviruses. Early acyclovir treatment may shorten symptoms, especially in severe or recurrent whitlow.
Cellulitis: A spreading bacterial infection of the skin and tissues beneath it, causing redness, warmth, and swelling. Cellulitis produces spreading inflammation rather than the characteristic grouped HSV blisters.
Herpes simplex encephalitis: A rare, serious brain infection caused by herpes simplex virus. This severe HSV disease illustrates why viral infection near the eye or nervous system warrants attention.