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Nurse management of benign skin lesions in the community

David de Berker
BA MB BS MRCP
Consultant Dermatologist
Bristol Dermatology Centre
Bristol Royal Infirmary
E:david.deberker@ubht.swest.nhs.uk

This article examines the treatment of the most commonly encountered bumps. More detailed accounts are needed as a basis for training and are available in the books by Lawrence and Dawber et al.(1,2)

Common bumps
The best rule of thumb when it comes to treating bumps is "keep it simple". Work with just two or three diagnoses and make sure that you know them inside out. I would suggest that seborrhoeic warts, viral warts and skin tags are a good core group of diagnoses.
Seborrhoeic warts are fantastically common - you could probably spend most of your working career removing these from people over the age of 50. They are often itchy and can be protuberant. They have a rough surface and may be regular or irregular in outline. Some are pink, some have a yellowish tinge and some are pigmented or mixed in colour. Because they stick out and because people scratch them due to the itch, it is common to find one that has bled. They are most common on the trunk and chest, but can also be found anywhere from the scalp to the feet. This collection of characteristics means that they share many features with skin cancer, and this is the reason for hospital referral by GPs for diagnosis and differentiation from a melanoma or squamous cell carcinoma.
Viral warts are usually found in younger patients and are particularly common on the hands. They are commonly treated by cryosurgery with liquid nitrogen spray, and are seldom treated by surgery.
Skin tags are usually easy to diagnose as they occur in clusters in the flexures of the axilla, groin or at the base of the neck. They are small, fleshy, skin-coloured tags, rarely more than a couple of millimetres across.
There are many benign bumps outside this list, but most will have less predictable outcomes in terms of treatment and also may pose more diagnostic problems. Included in this category are benign pigmented or nonpigmented moles. My reason for leaving them off the list is because it is much easier to go wrong with moles than other lesions. They are also more likely to recur after surgery unless you undertake more complex excisional surgery not described here. When they recur, the pattern of pigment may be bizarre, and this compels further, more elaborate surgery to exclude malignancy, which was not contemplated in the first instance but becomes an issue on recurrence.

Diagnosis
Rule number one is establish a diagnosis first. You will not be trained in dermatological diagnosis, and so it is advisable to work closely with your GP colleagues. You may gradually develop the skills to make a diagnosis yourself, but it is not likely that you will be accredited in dermatological diagnosis.
The most important reason for correct diagnosis is so that you do not confuse a skin malignancy with a benign bump. While it is fair to say that in patients under the age of 30 you are unlikely to encounter a skin malignancy, it is best not to rely on the laws of probability. In those over 30 years of age and especially in those over 60, it becomes increasingly likely that a benign lump needs to be distinguished from a skin cancer.
 
Swap a bump for a scar
Once you have a working diagnosis of a benign lump, you and your patient need to decide whether it is really necessary to do anything. Medicolegally you need to act in what you believe to be the best interests of your patient. It is not sufficient that they are convinced that it is a good idea. They are not experts in the outcome of skin surgery, but you are.
I would almost never remove something for cosmetic reasons. I am sure that often such procedures are fine - particularly when the cosmetic handicap is largely due to the physical nature of the bump. However, if the handicap is mainly psychological, then the reaction to the scar may be equally problematic.
The two main categories of bumps are bumps that itch or hurt and bumps that cause practical problems by getting in the way of something such as a bra strap. You are usually able to agree with the patient that these aspects  will be resolved or reduced by treatment, although the bump is going to be replaced by a scar, and sometimes the scar will be just as ugly as the bump. If you paint the worst case scenario, you will establish the patient's true motivation and ensure that treatment is warranted on practical grounds.

Procedures
When choosing a procedure you must make an overall patient evaluation, taking note of what drugs the patient is currently taking, how they will be affected by the wound care and whether they will affect healing, and also considering the patient's domestic situation in terms of wound care and time off work. All technical procedures will need a period of closely supervised practical training with an expert, as well as some book work to establish the principles and issues associated with the procedure. During this period and during normal practice it is helpful to determine if the patient saw the outcome differently from you and whether there were any objective problems.
A limited list of procedures includes:

  • Cryosurgery.
  • Delivery of local anaesthetic.
  • Curettage and cautery.
  • Shave or snip biopsy.

Cryosurgery
Cryosurgery is the delivery of a freezing substance to the skin surface to achieve a freeze burn. The freeze burn is destructive and so results in the removal of some superficial skin lesions. The depth of the burn is related to the duration of the freeze, and this is how you control the dose. The damage to surrounding tissue is also controlled by the duration of the freeze - if you want to minimise this, it is often best to deliver two smaller freezes rather than one big freeze.
The most common technique for cryosurgery involves liquid nitrogen, which freezes at temperatures around -197°C. It is delivered to the skin surface via a modified vacuum flask with a trigger that allows the liquid nitrogen to vaporise and escape via a nozzle. The size of the nozzle can be altered from big (size A) to small (size D) (see Figure 1). The first allows a large amount of liquid nitrogen to pour over the skin in a short period, while the latter allows just a small amount, barely achieving a significant freeze before the skin temperature warms up again.

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The delivery and storage of liquid nitrogen is an involved business. The most common method is to have it delivered by an industrial source to a group practice who have a storage facility in the form of a large insulated canister. Depending on the size of the canister, frequency of use and time of year, deliveries may need to be monthly or less often. The substance is covered by COSHH regulations.
Our website covers many of the basic issues and contacts for this service,(3) and the book by Dawber has a useful section on developing a nurse cryosurgery clinic.(2) There are alternative freezing materials that can be used, such as dimethyl ether/propane aerosol (Histofreezer or Wartner), which achieve a skin temperature of between 0 and -50°C. The patient can buy Wartner in the chemist and bring it to the practice for expert help with its use.
All the lesions mentioned at the beginning of this article can be treated with cryosurgery. However, remember the first rule - know what you are treating. There have been instances where a malignant melanoma has been treated with cryosurgery after a false diagnosis of a benign lesion. The tumour of course recurred, but much thicker. When the correct diagnosis was eventually made, the prognosis for the patient was significantly worse than if the correct diagnosis and treatment had been delivered first time round.
Finally, cryosurgery entails soreness, possibly blistering, ooze and crust. This carries with it the risk of scarring and altered or lost pigment - particularly important in people with dark skin. Many warts will require more than one treatment, and recurrence is common. The pain is such that this is not usually a good treatment for children.

Delivery of local anaesthetic
This is not a treatment in itself but is a very useful nursing procedure allied to skin surgery. It is a good first step to becoming familiar with other aspects of surgery, and may also help you form a close working relationship with the person in your practice who will be your mentor. You will help them by relaxing the patient and talking them through what is in fact the most painful part of most procedures. Many dermatology departments use dental syringes with single-use cartridges of local anaesthetic and screw-on needles. In my opinion, these are not needed and normal syringes with fine needles are adequate. The gauge of a needle is measured by the G number, and, paradoxically, the finer the needle, the larger the number. A range of needles are available between 25 and 27G (see Figure 2), and those with a longer shaft are preferable. This allows you to disperse the anaesthetic over a wider area without withdrawing and entering a new skin puncture site.

[[NIP19_fig2_36]]

The anaesthetic usually used is lignocaine 1% or 2% with or without adrenaline 1:200,000. The latter causes vasoconstriction. Before you read on - think why this could be useful? It has two functions. First, it reduces the blood flow in the area, which means that there will be less bleeding. Second, a side-effect of reduced blood flow is that the lignocaine will not be washed away from the injection site too quickly, and hence the duration of numbness is increased. Anaesthetic can alter the heartbeat if given in toxic doses. If adrenaline is used, the peak concentration of anaesthetic in the bloodstream that reaches the heart is much less, because the rate of release from the injection site is kept down.
Care must be taken when giving an anaesthetic injection to ensure that you do not inject directly into a blood vessel, as this will deliver a big dose of anaesthetic to the heart and could make the patient unwell. To avoid this withdraw the plunger on the syringe as you insert it. If you have hit a blood vessel, blood will come back into the syringe - a sign that you should relocate the needle.
A full understanding of the technique and issues surrounding anaesthetic injection needs to cover the topics of anatomy, the anaesthetic itself, and drug interactions with other medicines the patient may be taking.

Curettage and cautery
The curette is a modified spoon (see Figure 3) or loop (Figure 4) with a sharp edge. This edge can scrape over loose or crumbling tissues to remove it. It is a perfect tool for treating seborrhoeic warts, as these tend to be adherent to the skin surface and do not involve deep structures. They are different in texture from normal skin, thus making it easy for you to sense the interface between the wart and the underlying skin. The interface seldom has anything more than capillary blood vessels, so there should only be a little bleeding. But you would normally use cautery to even out the surface you have curetted and to stop any bleeding. This entails learning the basics of cautery machines. In general practice, the most simple machine is a hot-loop cautery. This is like a lightbulb filament. When the current flows, the cautery tip glows. This sterilises the tip and also means that when it touches flesh it cauterises the area and usually seals blood vessels. There is fine control in the temperature of the tip so that it seals the vessels rather than cutting through them, but otherwise it is a cheap and simple tool to use.

[[NIP19_fig3_36]]

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The combination of curettage and cautery normally leaves a small scar, mainly due to the cautery. An alternative is chemical cautery using aluminium chloride solution. This works well for very low-level bleeding when combined with a period of pressure upon the wound. However, unlike electrocautery, it will not recontour the surgical site to remove any uneven edges. It must also be recognised that it is a chemical burn and caustic in its own right. When applied to a cut without anaesthetic, it hurts a lot, and in large quantities can cause an unpleasant burn needing its own wound management.
Finally, curettage produces a specimen. In my practice I send everything to the laboratory for analysis. This often raises a few eyebrows with GPs, who are aware that the vast majority of things that they remove are completely benign. However, every now and again an unexpected result crops up. If you do not keep checking the clinical diagnosis against the laboratory diagnosis, you could find that you are kidding yourself about how good you are at making a diagnosis. That way, errors creep in. Although there is concern that the cost of the laboratory service reduces the profit to the GP practice of undertaking the treatment in the first place, I would argue that an accurate diagnosis is more important.

Shave or snip surgery
Sometimes it is the fact that the bump sticks out that causes practical problems. In this case it may be helpful to simply shave the bump off flush with the skin. There is a high chance of recurrence with this type of biopsy, especially if you are dealing with something that is seated deep in the skin. However, formal excisional surgery may not be a practical option. Also, the rate of recurrence may be so slow that it never causes further concern. Fleshy tags are often treated this way. A small bleb of anaesthetic beneath will enable you to cut them off with a scalpel blade or fine scissors before a touch of cautery to stop bleeding. Moles can also be removed in this way, but there are more concerns about recurrence, residual hairs and the appearance afterwards.
 
Before you start …
Before you start any treatment the patient must fully understand the procedure and the possible extent of scarring. This merits an article all to itself, but for the purposes of this article two points are important. First, some areas produce awful scars and some areas don't heal. Biopsies and even cryosurgery to the upper chest, front or back can produce keloid scars. These are thickened scars that may expand to produce a mark bigger than the original bump. This kind of reaction is greatest in young people where the skin is more tight in this area, and also in those of African origin.
Poor healing is a problem below the knee. This becomes much more important after middle age. The classic error is to freeze or curette a benign lesion on the shin of an elderly woman and turn a small seborrhoeic wart into a leg ulcer. The two main ways to minimise the risk of this are to deliver smaller doses of treatment to this area and then to combine treatment with a specific approach to wound healing. This may include obtaining the Doppler pressures in the leg beforehand and ensuring that the patient has some organised convalescence and will not be going on a hiking holiday!
Written consent is not a legal requirement, and many clinicians and patients feel that it is an unhelpful legalistic element to a procedure. However, genuine informed consent is essential, and for this the patient must fully understand the treatment and its sequelae and the discussion must be documented. There is no substitute for having plenty of time to talk to the patient, often to explain things twice and possibly to explain to a relative as well. Patient information leaflets can be helpful.
The patient must fully understand:

  • The procedure itself.
  • Complications that may arise.
  • Wound care.
  • Scarring and the possibility of recurrence.

Nurses ­undertaking skin surgery need to be accredited following a course of training and assessment. The facilities for this vary and may be best explored through the local hospital and dermatology department.

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References

  1. Lawrence CM. An introduction to dermatological surgery. London: Churchill Livingstone; 2002.
  2. Dawber R, Colver G, Jackson A. Cutaneous cryosurgery ­principles and clinical practice. 2nd edn. London: Martin Dunitz; 1997.
  3. Available from URL: http://www.ubht.nhs.uk/eDerm/cryo surgery.htm