Immunotherapy treatment for verrucae could revolutionise podiatry treatments for this challenging skin infection. The verruca or common wart ( verruca vulgaris) is caused by the Human Papilloma Virus (HPV). The same virus is responsible for body warts, but there are lots of sub types of this virus to include low and high risk strains. Over 200 HPV strains have been identified. The verruca strains are considered low risk not leading to malignancy. Types identified are 2,4 being the most common and 1,3,27,29 and 57.
The high risk HPV strains are responsible for more serious cancers like cervical and oral. Fortunately, there are only about 9 strains identified which cause malignancy. An individual can have HPV without realising it and develop an immune response without producing any symptoms or signs of infection.
What is an Immune Response?
An immune response occurs when the body protects itself by producing proteins called antibodies. Antibodies develop when there is an invading foreign body called an antigen like the HPV.
Verruca Immunity. Is it Pot-Luck?
In podiatry practice it is often observed in a family of 4-5 only 1 or 2 members have verrucae with the others being immune. It really can be pot- luck and does not necessarily mean one has a bad immune system. The HPV is a tricky antigen it has developed immune evasion strategies. There is no viremia, which means no presence of the virus in the blood stream. This makes it hard for the immune system to detect. There are no inflammatory signals. The interferon response for HPV infection, a key antiviral defence mechanism is suppressed, hence antibody production is suppressed. It may take months to register the HPV or it simply will not occur for years if not at all.
Research has shown that HPV can lay dormant in the body for years laying under the radar. It can then randomly erupt. Could this be the reason why adults suddenly develop verrucas? Podiatrists ask patients the usual questions; “Have you been to the gym or swimming?” to determine an etiological cause, but often there isn’t one. Stress could be identified as the trigger when the body immune system is run-down.
What is the incidence of verruca HPV?
The verruca HPV strain is world wide and affects approximately 10% of the population, being more common in white ethic groups. Babies and toddlers are immune, but the prevalence of getting an infection greatly increases with age, peaking at 12 -16 years. Hot sweaty hormonal feet you could argue, naturally developing immunity or sharing communal spaces like the gym and swimming pool? The virus does discriminate which foot it chooses. The virus likes damaged and moist skin to enable it’s passage into the epidermis. Contrary to popular belief it is not highly contagious.
Generally, youngsters respond well to conservative treatment options developing a rapid immune response. Sadly, not always the case with adults. If verrucae are not treated an immune response is expected to develop within 24 months with the infection spontaneously resolving. Individuals are not always patient enough to wait. Verruca can be painful, unsightly and spread. Not treating the infection does not seem like an option.
The latter waiting option is great if an immune response develops, but approximately a 1/3 of individuals don’t develop an immune response, by which point they have multiple growths on their feet or hands. Again it is pot-luck. It is hard to detect whether an individual will be lucky enough to get a natural regression of the infection. In a clinical setting it is impossible. How do you see and detect a virus, let alone peer in at the immune system? Basic blood tests can check out white blood cell count, but a more in-depth examination of the body’s immune system is expensive. This is reserved for high risk HPV groups.
Get Treating to Test out Verruca Immune Response
The only way to test out the immune system is to actively treat the infection. Most verruca treatments are all about mediating an immune response whether with keratolytic acids, freezing, needling or Swift microwave. Podiatrists are initially patch-testing to gauge response. If it known a patient is immuno-compromised, has poor health this will effect outcomes. Choice of treatment has to be considered as to which will be more effective. This tests the skill of the podiatrist and depends on what options are available in clinic. A laser treatment which works by tissue destruction may be better than needling or the Swift. The latter 2 options work on triggering an immune response.
What Happens if a Patient is Treatment Resistant?
There are those unfortunate individuals who have chronic treatment resistant verrucae infections. These individuals report having had infections for over 8-10 years plus. Nothing has worked. To stand any chance of an effective treatment it must be understood treatment needs to be aggressive. Tissue ablation and surgical excision can be highly effective using high powered long wave lasers or electrosurgery.
Once the infected tissue is removed a programme of post care vigilance is important. Short term application of topicals to minimise risk of re-infection. Taking care to protect feet in communal areas. Ensuring infected loved ones are also treated, but despite all efforts the verruca bounces back bigger and bolder.
What Happens Now?
Live with it? Conservatively manage it? See a dermatologist or immunologist? Go on prescribed interferon or imiquimod? Interferon is used to treat some cancerous conditions like leukemia and melanomas, but is can also treat some chronic viral infections effecting the liver in the case of hepatitis B. So theoretically it could work on the verruca HPV? Interferon is naturally part of the body’s immune system. A cytokine chemical which helps to protect against foreign intruders. Interferon does have lots of short term side-effects like nausea and diarrhea which may be worth putting up. The long term side-effects are autoimmune disorders like arthritis.
Imiquimod (Aldara) is a topical cream which is an immune response modifier. It treats genital and anal warts by increasing the activity of the body’s immune system. There is evidence to demonstrate it can work on verruca, but it can only be prescribed off-label. This means it has not gone through proper clinical trials for it’s efficacy in treating verrucae. It is more likely to be prescribed privately than by an NHS physician.
Cidofovir is another drug which helps the immune system to fight viral infections. It can be applied as cream or injected directly into a verruca to cause a resolution. Reports suggest it may be beneficial in patients with recalcitrant warts. Along a similar line the MMR vaccine has been injected into verrucae to trigger an immune response.
Immunotherapy does appear to be the way ahead. Incidentally Compleet Feet had a patient who out of desperation to resolve his treatment resistant verrucae had a course of 3 Gardasil injections. Gardasil is currently administered under the national NHS HPV vaccination programme as a vaccine to protect against cervical and genital cancer. It is a vaccine not an immune system booster to treat an existing virus, but it worked for the patient. Co-incidentally he had just had aggressive surgical debridement so was this just a co-incidence or did it help mediate an immune response?
Future of Immunotherapy for Verruca HPV
There are so many questions around immunotherapy and how it can help eradicate chronic verrucae infections. Little to no research is undertaken into immunotherapy for the verruca HPV. Cost makes it prohibitive and the Verruca HPV is low risk. Those treatments which are available are costly and not licensed for verruca treatments.
