Efficacy of topical imiquimod 3.75% in the treatment of actinic keratosis of the scalp in immunosuppressed patients: our case series

Actinic Keratoses: A Prospective Pilot Study on a Novel Formulation of 4% 5-Fluorouracil Cream and a Review of Other Current Topical Treatment Options

BACKGROUND

Actinic keratosis (AK) is one of the most common skin diseases, with a low risk of progression into invasive squamous cell carcinoma. We aim to assess efficacy and safety of a novel formulation of 5-Fluorouracil (5-FU) 4% with once daily application for the treatment of multiple AKs.

METHODS

A pilot study was performed on 30 patients with a clinical and dermoscopic diagnosis of multiple AKs, enrolled between September 2021 and May 2022 at the Dermatology Departments of two Italian hospitals. Patients were treated with 5-FU 4% cream once daily for 30 consecutive days. The Actinic Keratosis Area and Severity Index (AKASI) was calculated before starting therapy, and at each follow-up, to assess objective clinical response.

RESULTS

The cohort analyzed included 14 (47%) males and 16 (53%) females (mean age: 71 ± 12 years). A significant decrease in AKASI score at both 6 and 12 weeks (p < 0.0001) was observed. Only three patients (10%) discontinued therapy, and 13 patients (43%) did not report any adverse reactions; no unexpected adverse events were observed.

CONCLUSIONS

In the setting of topical chemotherapy and immunotherapy, the new formulation of 5-FU 4% proved to be a highly effective treatment for AKs and field cancerization.

Pharmacological Agents Used in the Prevention and Treatment of Actinic Keratosis: A Review

Actinic keratosis (AK) is among the most commonly diagnosed skin diseases with potentially life-threatening repercussions if left untreated. Usage of pharmacologic agents represents one of many therapeutic strategies that can be used to help manage these lesions. Ongoing research into these compounds continues to change our clinical understanding as to which agents most benefit particular patient populations. Indeed, factors such as past personal medical history, lesion location and tolerability of therapy only represent a few considerations that clinicians must account for when prescribing appropriate treatment. This review focuses on specific drugs used in either the prevention or treatment of AKs. Nicotinamide, acitretin and topical 5-fluorouracil (5-FU) continue to be used with fidelity in the chemoprevention of actinic keratosis, although some uncertainty persists in regard to which agents should be used in immunocompetent vs. immunodeficient/immunosuppressed patients. Topical 5-FU, including combination formulations with either calcipotriol or salicylic acid, as well as imiquimod, diclofenac and photodynamic light therapy are all accepted treatment strategies employed to target and eliminate AKs. Five percent of 5-FU is regarded as the most effective therapy in the condition, although the literature has conflictingly shown that lower concentrations of the drug might also be as effective. Topical diclofenac (3%) appears to be less efficacious than 5% 5-FU, 3.75-5% imiquimod and photodynamic light therapy despite its favorable side effect profile. Finally, traditional photodynamic light therapy, while painful, appears to be of higher efficacy in comparison to its more tolerable counterpart, daylight phototherapy.

Comparative study of imiquimod 3.75% vs. photodynamic therapy for actinic keratosis of the scalp

BACKGROUND/PURPOSE

To assess efficacy, tolerability, adverse effects, recurrence, and aesthetic results of imiquimod 3.75% vs. photodynamic therapy with 5-aminolaevulinic acid (MAL-PDT) for actinic keratosis (AK).

METHODS

A small randomized, intraindividual right-left pilot study for AK treatment of multiple scalp lesions was performed. Patients were treated with imiquimod and subsequently MAL-PDT (on opposite sides of the scalp) 14 days apart. Study end points were evaluated with clinical and dermoscopic examinations at 1, 3, 6, and 12 months.

RESULTS

Nine male bald patients were enrolled. Imiquimod achieved a slightly higher overall clearance rate than MAP-PDT (68.1% vs 56.5%). According to AK degree of severity, clearance rates were greater for degree I and III with imiquimod (68.8%, 64.5% and 75% with imiquimod vs. 48%, 69.8%, and 66.7% for MAL-PDT, respectively). At 12 months, a slightly higher total recurrence rate was noted for imiquimod compared with MAL-PDT (9.9% vs. 8.6%); new lesions were 2 degree I for imiquimod and 4 degree I for MAL-PDT. For both treatments, pain was moderate/strong (even if MAL-PDT seems to be less tolerable) adverse effects are common and transient; aesthetic results excellent.

CONCLUSION

Both imiquimod and MAL-PDT were effective in the reduction in the number of AK. In the long-term, both present a good effectiveness maintained over time with excellent aesthetic results. A combination or sequential therapy could optimize the management of the cancerization field.