Very early lesions that present with just a change in pigmentation or a rough texture may be left alone and just observed. These lesions if protected from sun exposure may improve without any treatment. All other lesions need to be treated to prevent them from evolving into squamous cell carcinoma. It is sometimes difficult to distinguish between an actinic keratosis and a thin squamous cell carcinoma. Areas such as the scalp and ears are especially difficult areas to distinguish between the 2 entities. If there is any doubt then the lesion should be treated with desiccation and curettage. Freezing superficial squamous cell carcinoma may treat the superficial part of the keratosis and leave the deeper part to progress.
The vast majority of actinic keratoses are treated by cryotherapy. This is a painful but highly effective procedure. Patients with discrete individual lesions are best treated with this modality. Patients with diffuse superficial actinic keratoses may be best treated with creams. This is a 3-6 week ordeal that is disfiguring and potentially painful. The results can be very gratifying and long lasting. Patients are evaluated one or 2 months later to treat any residual lesions with cryotherapy or electrodesiccation and curettage.
Liquid nitrogen is effectively delivered with a spray device. The nitrogen is most effective when it is sprayed rapidly. Nitrogen delivered by cotton tip applicator is a slow and less effective method. Experience will guide the clinician to how long to spray. The rim of freeze around the lesion should be at least one or 2 mm. Aggressive freezing may cause a giant blister to form. The procedure is acutely painful. The scalp and lower back are especially painful areas to treat.
Almost any area can be treated with cryotherapy. The face, scalp, chest, back, and extremities can be treated. Lesions close to the eye may be best treated with electrodesiccation and curettage. Giant blisters and bleeding can result with cryotherapy in this area.
Examine patient’s 2 or 4 months later to retreat keratoses that did not completely respond.
5-fluorouracil cream has been used for over 30 years to successfully treat superficial actinic keratoses. The cream is available in various concentrations. The 2 most commonly used products are Efudex cream and Carac. This cream is applied twice each day. Carac is 5-fluorouracil delivered in an optimum base. Both medications produce the same result. Carac is only applied once each day.
Most lesions on the face require 3-4 weeks of treatment. Thicker lesions on the extremities may require longer treatment and may not respond completely. These lesions may have to be treated at a later date with cryotherapy or electrodesiccation and curettage.
Medications are treated until moderate to intense inflammation with redness and scaling is achieved. This is called the lesion disintegration phase. It is best to see the patient at 3 weeks into treatment to determine if treatment can be discontinued or needs to be extended for another week or 2. Patients at the three-week period often are very concerned and need evaluation and guidance. Pharmaceutical manufacturers of these products make educational material available for the patient. These are especially useful because they show pictures of the intense inflammation.
It takes to 4 weeks after stopping application of the cream to recover. Patients may develop a low-grade infection especially if the inflammation is intense. Those presenting with crusting or purulent material should be treated with either topical antibiotics such as mupirocin or oral antibiotics such as cephalexin.
This product has been available for about 10 years. It is an immune modulating drug. The cream is supplied in small quantities in individual packets. These packets are supplied in a box. This packaging is required by the FDA because of the nature of the medication. It is inconvenient to use. Patients may either tear open the packet or puncture it with a pin.
Imiquimod is available in a generic form in a 5% concentration. A newer brand-name form called Zyclara 3.75% is available in a box of 28. It is applied once each day to the entire affected area for 2 weeks. This is followed by a 2-week rest period and then an additional 2 weeks of treatment. The 5% preparations can be used on a similar schedule. Imiquimod 5% can be applied twice each week for 16 weeks. There are many other possible schedules.
The endpoint of treatment is the same as for 5-fluorouracil. Lesions become highly inflamed and then disintegrate. Follow patients to evaluate the degree of inflammation. Moral support is also required during use of this unpleasant form of treatment. Patients will remain clear for months to years after a course of treatment.
Diclofenac is an anti-inflammatory topical cream approved for treating actinic keratoses. The cream is applied for 60-90 days and does not cause the same degree of inflammation as fluorouracil or imiquimod. The drug is marginally effective and is best reserved for patient’s who could not tolerate the inflammation produced by the other drugs.
Electrodesiccation and curettage
This technique is effective for individual lesions. It is the treatment of choice if there is any doubt about the depth of the keratosis. It can cause minor scarring but the cosmetic result is usually acceptable. The technique is often employed for treating lesions on the scalp. Determination of lesion depth in this area is often difficult by just simple physical examination. The technique is also useful for lesions around the eye.
Keratoses on the arms, back of the hands and legs may be too thick to respond to cryotherapy or fluorouracil. A large number of these keratoses can be treated in a single session with electrodesiccation and curettage.
This technique is reserved for lesions in which the diagnosis of squamous cell carcinoma is a possibility. Surgical incision is to radical procedure for actinic keratoses.
A light-sensitizing compound such as delta aminolevulinic acid is applied and accumulates in the keratoses. It is then exposed to light of an appropriate wavelength and results in cell death. The treatment is effective but expensive. It is not available in every dermatologist office.