Flat warts are an infectious skin disease caused by HPV, the human papillomavirus, and because current medical technology has no treatment that completely removes the virus itself, recurrence after treatment is not uncommon. The fact that recurrence is unavoidable does not mean that treatment itself is meaningless; the frequency of recurrence and the extent to which lesions spread differ greatly depending on when diagnosis and treatment are received, the treatment method, and lifestyle care afterwards.
This column sets out, in order, why flat warts recur, the treatment conditions that lower the recurrence rate, and the lifestyle care that follows.
Why do flat warts keep coming back?
Flat warts are skin-coloured papules about the size of a grain of rice, and because they cause no pain they are easily mistaken for a blemish. What sets them apart from acne is that they spread by touch, so 2 to 3 can increase to dozens or hundreds.
There is no treatment that removes HPV, so even after removal by laser or cryotherapy, the warts recur if the virus remains. Flat warts are an infectious disease that calls for recurrence management rather than a complete recovery.
Which treatment conditions should be checked to lower the recurrence rate?
Large warts are easily seen with the naked eye, but minute lesions at the 0.1mm level are easily missed without a precise diagnosis. Because of the virus that remains, new lesions appear again even after removal.
If only the epidermis is stimulated, the root remains and the wart recurs; if the treatment is excessive, scarring and pigmentation remain. Adjusting the energy by size and depth and protecting normal tissue therefore determine the recurrence rate.
- Energy adjustment — the laser energy must be adjusted to the size and depth of the lesion so that it is destroyed down to the root while damage to normal tissue is reduced
- Precise diagnosis — even minute lesions at the 0.1mm level must be found so that virus remaining in places not visible to the naked eye is not missed
- Treatment at sufficient depth — the laser must reach a depth that touches the root of the lesion without leaving a scar in order to prevent rapid recurrence
What lifestyle care is needed after treatment?
It is hard to say that recurrence can be avoided 100 percent, and when immunity drops, the body's defence against the virus also weakens and recurrence becomes easier. Touching the face frequently spreads the warts, so this habit should be corrected first.
Strongly irritating care such as scrubs and peels weakens the skin barrier and invites the virus to recur, so it should be avoided for some time after the lesions have gone. Puffs, phones, towels and bedding that touch the face should be kept thoroughly hygienic to prevent reinfection and spread.
- Not touching with the hands — this is the most common route by which the virus spreads even to areas without lesions, so the habit of touching and rubbing should be corrected first
- Avoiding irritating care — care that irritates the skin, such as scrubs or peels, weakens the skin barrier and raises the risk of recurrence
- Hygiene — items that come into direct contact with the face, such as puffs, smartphones, towels and bedding, should be kept clean at all times
