Disseminated Superficial Actinic Porokeratosis in a Patient with Psoriasis, after Long-Term Narrowband Ultraviolet B Phototherapy

Porokeratoses-A Comprehensive Review on the Genetics and Metabolomics, Imaging Methods and Management of Common Clinical Variants

Porokeratosis is a heterogeneous group of keratinising disorders characterised by the presence of particular microscopic structural changes, namely the presence of the cornoid lamella. This structure develops as a consequence of a defective isoprenoid pathway, critical for cholesterol synthesis. Commonly recognised variants include disseminated superficial actinic porokeratosis, disseminated superficial porokeratosis, porokeratosis of Mibelli, palmoplantar porokeratosis (including porokeratosis palmaris et plantaris disseminata and punctate porokeratosis), linear porokeratosis, verrucous porokeratosis (also known as genitogluteal porokeratosis), follicular porokeratosis and porokeratoma. Apart from the clinical presentation and epidemiology of each variant listed, this review aims at providing up-to-date information on the precise genetic background, introduces imaging methods facilitating the diagnosis (conventional and ultraviolet-induced fluorescence dermatoscopy, reflectance confocal microscopy and pathology), discusses their oncogenic potential and reviews the literature data on the efficacy of the treatment used, including the drugs directly targeting the isoprenoid-mevalonate pathway.

Safety and Efficacy of Topical Lovastatin Plus Cholesterol Cream vs Topical Lovastatin Cream Alone for the Treatment of Disseminated Superficial Actinic Porokeratosis: A Randomized Clinical Trial

Importance

Disseminated superficial actinic porokeratosis (DSAP) is an inherited or sporadic disorder of keratinization associated with germline variations. There is no effective standard of care therapy for DSAP, but treatment with topical lovastatin combined with cholesterol cream has shown promise.

Objectives

To evaluate and compare the safety and efficacy of topical lovastatin 2% plus cholesterol 2% cream (lovastatin-cholesterol) and topical lovastatin 2% cream (lovastatin) alone in adults diagnosed with DSAP.

Design, Setting, and Participants

This patient- and assessor-blinded, randomized clinical trial was conducted at the Medical University of South Carolina between August 3, 2020, and April 28, 2021. Nonpregnant adults with a previous clinical or histological diagnosis of DSAP were eligible. Data were blindly analyzed after study completion.

Interventions

Participants were randomized to once- or twice-daily application of either lovastatin-cholesterol cream (n = 17) or lovastatin cream (n = 14) to symptomatic regions for 12 weeks.

Main Outcomes and Measures

The primary efficacy measure was the effect of the treatment on DSAP at the end of treatment (12 weeks) as measured by the DSAP General Assessment Severity Index (DSAP-GASI; scored from 0-4, with 0 indicating clear and 4 indicating severe). Treatment efficacy was based on investigator-standardized photographs provided by the participants because of the need for evaluation via telehealth during the COVID-19 pandemic. Secondary efficacy measures included patient-reported outcomes, application frequency, and adverse events (AEs).

Results

Of the 87 participants screened, 32 were enrolled. One participant randomized to receive lovastatin-cholesterol did not receive the intervention, leaving 17 participants (mean [range] age, 59.2 [40-83] years; 13 females [76.5%]; all White) allocated to receive lovastatin-cholesterol treatment and 14 participants (13 female [92.9%]; mean (range) age, 53.7 [33-71] years; all White) to receive lovastatin treatment. Twelve participants in each treatment group qualified for the analysis. Disease severity decreased from week 1 to week 12 by 50.0% (from 3.08 [95% CI, 2.57-3.60] to 1.54 (95% CI, 1.04-2.05] points on the DSAP-GASI; P < .001) in the lovastatin-cholesterol group and 51.4% (from 2.92 [95% CI, 2.40-3.43] to 1.50 [95% CI, 0.99-2.01] points; P < .001) in the lovastatin group. There was no significant difference between the treatment groups according to application frequency at the end of 12 weeks. Adverse events reported included myalgia (n = 2), elevation in the creatine kinase level (n = 1), application discomfort (n = 4), and rash (n = 1). No serious AEs occurred, and all participants with an AE were able to complete the study.

Conclusions and Relevance

This randomized clinical trial found improvements in DSAP severity in both treatment groups, without serious AEs, indicating a limited benefit with the addition of cholesterol. These results suggest that lovastatin cream may be a new primary treatment option for patients diagnosed with DSAP.

Trial Registration

ClinicalTrials.gov Identifier: NCT04359823.

Drugs associated with development of porokeratosis: A systematic review

Porokeratosis is a rare disorder characterized by atrophic macules or patches, with a well-defined ridge-like hyperkeratotic border called cornoid lamella. Although the exact pathogenesis is unknown, drug associated cases have recently been reported in the literature. As such, we systematically reviewed and identified drugs associated with drug-induced porokeratosis, their resultant effects, and whether there was a casual relationship between the use of a drug and the development of porokeratosis. We searched for articles which reported drug-induced porokeratosis in MEDLINE and Embase in June 2020. After full-text review, 25 studies were included for analysis. We identified 26 patients with drug-induced porokeratosis. The most common therapies associated with development of porokeratosis is biologic use, phototherapy, and radiotherapy. The most common clinical variants were the disseminated superficial or actinic types (60%), which occurred in psoriasis patients undergoing phototherapy, and eruptive disseminated type (24%) which occurred in the context of biologic therapies. The Naranjo score ranged from possible to probable for the identified treatments. Clinicians should consider drug reactions as possible triggering events for porokeratosis, especially for patients taking biologics, phototherapy, and radiotherapy. Large-scale studies are required to confirm our findings and further explore the pathogenesis for drug-induced porokeratosis.