Porokeratosis in patients with polycythemia rubra vera: a new side effect of hydroxyurea?

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.

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.

Hydroxyurea: a reappraisal of its cutaneous side effects and their management

Hydroxyurea (HU) is known to cause a broad spectrum of cutaneous side effects, ranging from relatively benign to severe. Although dermatologists are often consulted for the treatment of these side effects, a comprehensive resource discussing the different types and their management is lacking. In this study, we conducted a literature search in order to critically evaluate the reported types and management of hydroxyurea's cutaneous side effects, as well as review its mechanism of action, dermatologic uses, and common systemic side effects. Relatively common and benign side effects include hyperpigmentation, xerosis, and skin atrophy. While serious cutaneous side effects such as leg ulcers or nonmelanoma skin cancers occur in a substantial proportion of patients, these may resolve with HU discontinuation and proper dermatologic management. Therefore, it is crucial for dermatologists to be aware of these various cutaneous side effects and their management as prompt diagnosis and proper treatment will improve patient outcomes.

Disseminated Porokeratosis with Idiopathic Thrombocytopenia - Case Report and Literature Review of Porokeratosis and Related Disorders

BACKGROUND:

Porokeratosis is characterised by one or more atrophic patches surrounded by a distinctive peripheral keratotic ridge, typically found on sun-exposed areas, with several clinical variants and typical histological findings. Despite ultraviolet radiation, varies antibody - related autoimmune disease treated with systemic steroids and other immunosuppressive conditions such as chronic liver disease, HIV and organ transplantations have been implicated in its etiopathology.

CASE REPORT:

We present a case of porokeratosis, associated with idiopathic thrombocytopenia in 74 - year old, otherwise healthy male patient, as we discuss the previously reported associated disorders.

CONCLUSION:

Regarding all of the polymorphism of clinical presentation, associated disorders and treatment responses, we could conclude that disseminated porokeratosis is still an unknown well disorder, which will continue to surprise the physicians in future. The screening and follow up of the patients is mandatory in all cases because as we see, porokeratosis has multiple unexpected faces, which require circumstantial clinical and paraclinical behaviour.