Medicated creams and solutions are very effective by themselves or in combination with another form of treatment when a person has many actinic keratoses.
5-fluorouracil (5-FU) ointment or liquid in concentrations from 0.5 to 5 percent has FDA approval and is the most widely used topical treatment for actinic keratoses. It is effective against not only the surface lesions but also the subclinical ones. Rubbed gently onto the lesions once or twice a day for two to four weeks, it produces cure rates of up to 93 percent. Reddening, swelling and crusting may occur, but they are temporary. The lesions usually heal within two weeks of stopping treatment. There is rarely scarring and the cosmetic result is good.
Imiquimod 5% cream, also FDA-approved, works in a different way: It stimulates the immune system to produce interferon, a chemical that destroys cancerous and precancerous cells. It is rubbed gently on the lesion twice a week for four to sixteen weeks. The cream is generally well-tolerated, but some individuals develop redness and ulcerations.
Diclofenac is a non-steroidal anti-inflammatory drug used in combination with hyaluronic acid, a chemical found naturally in the body. The resulting gel is applied twice a day for two to three months. The diclofenac prevents an inflammatory response, so this topical is well-tolerated, and the hyaluronic acid delays uptake of the diclofenac, leading to higher concentrations in the skin. It is used in persons who are oversensitive to other topical treatments.
In 2012, the FDA approved an effective new topical medicine called Picato® (ingenol mebutate). Available in concentrations of 0.015 and 0.05 percent depending on the AK site, this gel is the first topical therapy to treat AKs effectively with just two or three days application time – three consecutive days for the 0.015% concentration (used on the face and scalp) and two consecutive days for the more concentrated 0.05% gel (used on the trunk and extremities). Skin redness, flaking/scaling, crusting, and swelling are the most common side effects. Picato can cause painful reactions in the first days of treatment, but these usually begin to abate within a week of starting treatment.
This is the most commonly used treatment method when a limited number of lesions exist. No cutting or anesthesia is required. Liquid nitrogen, applied with a spray device or cotton-tipped applicator, freezes the growths. The lesions subsequently shrink or become crusted and fall off. Temporary redness and swelling may occur after treatment, and in some patients, white spots may remain permanently.
If one form of therapy is good, two may be better; some of the treatment options described here are especially effective when used together or in sequence. This approach can both improve the cure rate and reduce side effects. One to two weeks of 5-FU followed by cryosurgery can reduce the healing time for 5-FU and decrease the likelihood of white spots following cryosurgery.
This method, best known for reversing the signs of photoaging, is also used to remove some actinic keratoses on the face. Trichloroacetic acid (TCA) and/or similar chemicals are applied directly to the skin. The top skin layers slough off and are usually replaced within seven days. This technique requires local anesthesia and can cause temporary discoloration and irritation.
A carbon dioxide or erbium YAG laser is focused onto the lesion, and the beam cuts through tissue without causing bleeding. This is a good option for lesions in small or narrow areas, and, therefore, can be particularly effective for keratoses on the face and scalp, as well as actinic cheilitis on the lips. However, local anesthesia may be necessary, and some pigment loss can occur. Lasers are useful for people taking blood thinners or as a secondary treatment when others have not succeeded.
Photodynamic Therapy (PDT)
PDT can be especially useful for lesions on the face and scalp. Topical 5-aminolevulinic acid (5-ALA), a photosensitizing agent, is applied to the lesions. Subsequently, the medicated area is exposed to strong light that activates 5-ALA. The treatment selectively destroys actinic keratoses, causing little damage to surrounding normal skin, although some swelling and redness often occur.