Verrucas and Warts
What are the clinical features of viral warts?
Warts have a hard surface. A tiny black dot may be observed in the middle of each scaly spot, due to a thrombosed capillary blood vessel.
Common warts present as papules with a rough, hyperkeratotic surface ranging in size from 1 mm to larger than 1 cm. They arise most often on the backs of fingers or toes, around the nails—where they can distort nail growth—and on the knees. Sometimes they resemble a cauliflower; these are known as butcher’s warts.
Plantar warts (verrucas) include tender inwardly growing and painful ‘myrmecia’ on the sole of the foot, and clusters of less painful mosaic warts. Plantar epidermoid cysts are associated with warts. Persistent plantar warts may rarely be complicated by the development of verrucous carcinoma.
Plane warts have a flat surface. The most common sites are the face, hands and shins. They are often numerous. They may be inoculated by shaving or scratching, so that they appear in a linear distribution (pseudo-Koebner response). Plane warts are mostly caused by HPV types 3 and 10.
Filiform warts are on a long stalk like a thread. They commonly appear on the face. They are also described as digitate (like a finger).
Topical treatment includes wart paints containing salicylic acid or similar compounds, which work by removing the dead surface skin cells. Podophyllin is a cytotoxic agent used in some products, and must not be used in pregnancy or in women considering pregnancy.
The paint is normally applied once daily. Treatment with wart paint usually makes the wart smaller and less uncomfortable; 70% of warts resolve within twelve weeks of daily applications.
- Soften the wart by soaking in a bath or bowl of hot soapy water.
- Rub the wart surface with a piece of pumice stone or emery board.
- Apply wart paint or gel accurately, allowing it to dry.
- Covered with plaster or duct tape.
If the wart paint makes the skin sore, stop treatment until the discomfort has settled, then recommence as above. Take care to keep the chemical off normal skin.
Cryotherapy is normally repeated at one to two–week intervals. It is uncomfortable and may result in blistering for several day or weeks. Success is in the order of 70% after 3-4 months of regular freezing.
A hard freeze using liquid nitrogen might cause a permanent white mark or scar. It can also cause temporary numbness.
An aerosol spray with a mixture of dimethyl ether and propane (DMEP) can be purchased over the counter to freeze common and plantar warts. It is important to read and follow the instructions carefully.
Combining Immunotherapy with cryotherapy reduces the number of cryotherapy sessions.
Electrosurgery (curettage and cautery) is used for large and resistant warts. Under local anaesthetic, the growth is pared away and the base burned. The wound heals in two weeks or longer; even then 20% of warts can be expected to recur within a few months. This treatment leaves a permanent scar.
The CO2 laser and verruca vulgaris
Verruca vulgaris, or a common wart, is a benign epithelial contagious tumour. It is usually flesh-coloured hyperkeratotic papule of a small size (few millimetres in diameter) although sometimes it may reach up to 2 cm in diameter. Milder, more conservative chemical therapy often requires weeks or months and is often unsuccessful. More aggressive therapy (e.g. electrodesiccation and curettage) may result in significant morbidity, tissue damage, and scarring. Plantar warts are particularly problematic. CO2 laser has numerous applications in dermatology and dermatologic surgery. It is versatile, being either a vaporising tool or a light scalpel. CO2 laser is an excellent modality for treating problematic or recurrent warts. In our experience it has now become the method of choice for warts
Verruca vulgaris most often occurs on fingers and hands of children and teenagers (most commonly between ages 18 to 20). Resistance to therapy is common, and recurrences are frequent. Carbon dioxide laser is a high-precision, bloodless light scalpel used for incising and excising tissues with sealing of small blood vessels. It is the treatment of choice for local destruction of intraephithelial neoplastic lesions. The carbon dioxide beam may be used to remove tissue in one of two ways. First, the lesion may be vaporized until a bed of healthy tissue is reached. The second and better technique is to use the beam as a scalpel to excise a lesion with appropriate margins. Post-operative morbidity and complications are low, and long-term results appear to be excellent.