Warts are tumours or growths of the
skin caused by infection with Human Papillomavirus (HPV). More than
70 HPV subtypes are known.
Warts are particularly common in childhood and are spread by direct
contact or autoinocculation. This means if a wart is scratched,
the viral particles may be spread to another area of skin. It may
take as long as twelve months for the wart to first appear.
What do they look like?
Warts have a hard ‘warty’ or ‘verrucous’ surface. You can often
see a tiny black dot in the middle of each scaly spot, due to a
thrombosed capillary blood vessel. There are various types of viral
wart.
- Common warts arise most often on the backs of fingers or
toes, and on the knees.
- Plantar warts (verrucas) include one or more tender inwardly
growing ‘myrmecia’ on the sole of the foot.
- Mosaic warts on the sole of the foot are in clusters over
an area sometimes several centimetres in diameter.
- Plane, or flat, warts can be very numerous and may be innoculated
by shaving.
- Periungual warts prefer to grow at the sides or under the
nails and can distort nail growth.
- Filiform warts are on a long stalk.
- Oral warts can affect the lips and even inside the cheeks.
-
Genital warts are often transmitted sexually and predispose
to cervical and vulval
cancer.
Common warts |
Common warts |
Cauliflower wart |
Plantar warts |
Mosaic warts |
Warts due to immunosuppression |
Plane warts |
Plane warts |
Subungual warts |
In children, even without treatment, 50% of warts disappear within
6 months; 90% are gone in 2 years. They are more persistent in adults
but they clear up eventually.
Warts are particularly numerous and troublesome in patients that
are immunosuppressed, most often due to medications such as
azathioprine or
ciclosporin. In these patients, the warts almost never disappear
despite treatment.
Treatment
Many people don't bother to treat them because treatment can be
more uncomfortable and troublesome than the warts - they are hardly
ever a serious problem. However, warts may be painful and they often
look ugly and cause embarrassment.
To get rid of them, we have to stimulate the body's own immune system
to attack the wart virus. Persistence with the treatment and patience
is essential!
Occlusion
Just keeping the wart covered 24 hours of the day may result in
clearance. Duct tape is convenient and inexpensive.
Chemical treatment.
Chemical treatment includes wart paints containing
salicylic acid or similar compounds, which work by removing
the dead surface skin cells. Podophyllin is a cytotoxic agent, and
must not be used in pregnancy or in women considering pregnancy.
The paint is normally applied once daily. Perseverance is essential
- although 70% of warts will go with wart paints, it may take twelve
weeks to work! Even if the wart doesn't go completely, the wart
paint usually makes it smaller and less uncomfortable.
First, the skin should be softened in a bath or bowl of hot soapy
water. The hard skin should be rubbed away from the wart surface
with a piece of pumice stone or emery board. The wart paint or gel
should be applied accurately, allowing it to dry. It works better
if covered with plaster or duct tape (particularly recommended when
the wart is on the foot).
Stronger preparations such as Upton's paste are used for thick verrucas,
applied every few days. It is important to protect the surrounding
skin with adhesive plaster before applying Upton's paste, and to
apply a plaster over the paste to keep it in place.
If the chemical makes the skin sore, stop treatment until the discomfort
has settled, then recommence as above. Take care to keep the chemical
off normal skin.
3% formalin solution can be used to soak multiple mosaic plantar
warts several times a week. Protect unaffected skin with Vaseline,
and apply cotton wool soaked in the solution, left in place for
about ten minutes before rinsing off.
Cryotherapy
The wart is frozen with
liquid nitrogen repeatedly, at one to three week intervals.
This is uncomfortable for a few minutes and may result in blistering
for several days. Success is in the order of 70% after 3-4 months
of regular freezing. Dermatologists debate whether a light freeze
to stimulate immunity is sufficient, or whether a harder freeze
is necessary to destroy all the infected skin. A hard freeze might
cause a permanent white mark or scar.
Electrosurgery
Electrosurgery
(curettage & cautery) is used for particularly large and annoying
warts. Under local anaesthetic, the growth is pared away and the
base burned by diathermy or cautery. The wound heals in about two
weeks; even then 20% of warts can be expected to recur within a
few months.
Other treatments
There are numerous treatments for warts and none offer a guarantee
of cure. They include bleomycin injections, laser vaporisation,
oral
acitretin and immune modulators such as
imiquimod cream.
Related information
Other web sites:
Nongenital warts - from emedicine dermatology, the online textbook
Books about
skin diseases:
See the
DermNet
NZ bookstore |