It is well known the efficacy of 5% 5-fluoruracil for multiple and superficial actinic keratosis (AKs)treatment. Recently its additional benefit for advanced and severe photoaging while treating Aks was reported.

The aim of this study is to compare the efficacy and safety of the two modalities of 5% 5-FU use for forearms photoaging.

The use of 5% 5-fluorouracil (5-FU) cream, twice a day, during 3 weeks represents a classic treatment for multiple and superficial AKs. The main adverse event is the severe skin irritation leading to interruption of the treatment in some cases. In the last decade a superficial pulse-peeling using it as agent in sequential applications was described. This modality of treatment has been demonstrated efficacy and better tolerability.

The improvement of the overall aspect of photodamaged skin is observed while treating multiple AKs.

There are no comparative study between the two types of 5% 5-FU use. So that is the purpose of our clinical trial.

Inclusion Criteria:

1. Healthy Men and women, aged from 50 to 75 anos;
2. Phototype I a III (Fitzpatrick Classification);
3. Advanced photoaging on forearms, with multiple superficial actinic keratosis;
4. Agreement with no sun exposure during the study and
5. Agreement with study conditions,capacity to understand and follow the orientations and form consent signature.

Exclusion Criteria:

1. Topical treatment with:

   • tretinoin in the last 6 months ;
   • other retinoids, alpha-hydroxyacids, poli-hydroxyacids, beta-hydroxyacids and ascorbic acid in the last 3 months;

2. Treatment by chemical peeling, microdermabrasion and non-ablative laser in the last 3 months;

3. Treatment with systemic retinoid in the last 6 months ;

4. Chemotherapy in the last 3 months;

5. Hypersensibility to parabens;

6. Infectious or inflammatory dermatosis on forearms;

7. Clinical evidence of immunosuppression and

8. Presence of photodermatosis