Warts

The human papilloma virus (HPV) infecting the skin is the cause of common warts. 

The specific HPV strains that produce common warts are different than those that create genital warts or cervical cancer. So these should be thought of as completely different issues.  Warts are rough or scaly, skin-colored papules or bumps most commonly seen on the hands or feet.  

They spread by skin-on-skin contact or through fomites like towels or clothing.  Common warts do not cause cancer but can be frustratingly persistent, taking between several months to 2 years to resolve. 

In the simplest view, wart treatments all produce localized inflammation, recruiting the immune system to come in and mount a defense against the HPV virus.  Several options are available:

1) Topical irritants: Examples are salicylic acid liquid or tape.  These products can be purchased over the counter (OTC) and applied at home.  They can be effective for some but typically take several months of treatment to cure warts.
2) Freezing with liquid nitrogen: OTC products are available but I have found that they can be pretty weak.  A dermatologist has access to a more powerful liquid nitrogen spray that can be effective but it may take several rounds of treatments.
3) Curettage:  Curetting the wart can be effective but should be done only by a healthcare professional.  After numbing the skin, the wart is scraped away in a controlled fashion with a sterile metal curette.  This can leave a nice cosmetic result but there is a risk that the warts recur.
4) Blistering beetle juice: Yes, you heard that right! The extract of the blistering beetle is applied in clinic and is washed off at home after several hours. Over the next few days, a thin blister will form that typically lasts for about 1-2 weeks.  It’s applied painlessly and quickly so it remains my go-to for squirmy kids.
5) Prescription creams: Examples are topical Imiquimod or 5-Fluorouracil.  They are effective but require the commitment of applying it several times a week for months at a time.
6) In-office injections: Examples are Candida yeast antigen or Bleomycin.  Injections directly into warts will create local inflammation that typically lasts 1-3 weeks.  I usually don’t reach for this first because the injections are painful, but it is an option for someone who’s failed others and is motivated. 
7) Shave removal: After numbing, the warts can be shaved off with a flat Gillette blade in clinic.  I don’t like doing this for my patients because it can leave a circular scar and there is a risk that the wart recurs.

Common warts are certainly a test of patience as many people undergo several treatments before seeing success.  Talk to your dermatologist about your options as he or she can get you to the best results.