Incision of a paronychia may be the very first procedure that I ever did in my medical career, and because of that, it has always held a special place in hierarchy of medical conditions we manage. Generally it is a simple diagnosis and simple procedure (that must be why my simple brain likes it). The purulence is contained superficially, along the edge of the fingernail, and easily extracted.
A Felon (also known as a Whitlow) is slightly more complicated, however, as it involved the deep pulp space of the finger and, hence, requires a more substantial incision and drainage. This is still a “rewarding” and useful procedure… at least once you deal with the patient’s pain and anxiety.
But before you numb that digit and perform a incision extending across the entire width of the digit, first consider one thing: is this a Herpetic Whitlow?
Herpetic Whitlow basics
- Due to HSV infection of the distal phalanx.
- Is actually a misnomer: “Whitlow” refers to a painful, pus-producing infection of the deep space of the finger. Herpetic Whitlows do not have purulence, so not really a “whitlow”… but let’s not quibble over semantics.
- Often associated with:
- In children – primary gingivostoatitis and autoinoculation, or trauma
- In Adolescents/Adults – may be associated with genital HSV infections
- In Adults – often are medical professionals who get inoculated by patients (so wear gloves!
- May have antecedent pain and tingling of the fingertip.
- Swelling and redness then occurs.
- Fevers, constitutional symptoms, lymphadenopathy can be present.
- Then appear one or more vesicles that enlarge and can become coalescent.
- The central, large collection of vesicles can be easily confused for superficial purulence… so look for smaller vesicles on the periphery.
- The vesicles remain for 7-10 days and eventually crust over.
- Peeling occurs within week, revealing normal skin. (it is a self-limited condition)
- Easily mistaken for a bacterial felon, which can lead, unfortunately, to unnecessary and potentially harmful I+D
- Look for vesicles!
- Check mouth and other mucous membranes for vesicles.
- Herpetic Whitlow usually will not have tense pulp space like Felon.
- Serous drainage rather than purulence
- Consider Tzack smear (should be rapid, culture takes too long).
- If your lab does not perform Tzank smears, you can also order a viral DFA (which is super quick) in the pink viral transport media to look for HSV 1,2, varicella.
- Unfortunately, super-infection can also occur… again, your job is tough!
Treatment for Herpetic Whitlow
- Avoid I+D (may increase risk for super-infection and won’t help it heal)
- Pain management
- Dry Dressings (to help limit further spread)
- Consider needle-aspiration of larger, tense vesicles.
- Acyclovir/valacyclovir can be used… but not studies about this specific use… but reasonable if it has only been 1-2 days of symptoms.
Feder HM, Long SS. Herpetic Whitlow: Epidemiology, Clinical Characteristics, Diagnosis, and Treatment. Am J Dis Child. Sept 1983; 137: 861-863