Photoallergic dermatitis induced by diltiazem

Drug-Induced Photosensitivity-From Light and Chemistry to Biological Reactions and Clinical Symptoms

Photosensitivity is one of the most common cutaneous adverse drug reactions. There are two types of drug-induced photosensitivity: photoallergy and phototoxicity. Currently, the number of photosensitization cases is constantly increasing due to excessive exposure to sunlight, the aesthetic value of a tan, and the increasing number of photosensitizing substances in food, dietary supplements, and pharmaceutical and cosmetic products. The risk of photosensitivity reactions relates to several hundred externally and systemically administered drugs, including nonsteroidal anti-inflammatory, cardiovascular, psychotropic, antimicrobial, antihyperlipidemic, and antineoplastic drugs. Photosensitivity reactions often lead to hospitalization, additional treatment, medical management, decrease in patient's comfort, and the limitations of drug usage. Mechanisms of drug-induced photosensitivity are complex and are observed at a cellular, molecular, and biochemical level. Photoexcitation and photoconversion of drugs trigger multidirectional biological reactions, including oxidative stress, inflammation, and changes in melanin synthesis. These effects contribute to the appearance of the following symptoms: erythema, swelling, blisters, exudation, peeling, burning, itching, and hyperpigmentation of the skin. This article reviews in detail the chemical and biological basis of drug-induced photosensitivity. The following factors are considered: the chemical properties, the influence of individual ranges of sunlight, the presence of melanin biopolymers, and the defense mechanisms of particular types of tested cells.

Cardiovascular Drug Use and Risk of Actinic Keratosis: A Case-Control Study

INTRODUCTION

Actinic keratosis (AK) is a precancerous skin lesion. Currently, many experts treat actinic keratosis as squamous cell carcinoma in situ. It is well established that exposure of the skin to ultraviolet radiation is a major risk factor for the development of actinic keratosis. Some studies suggest an association between keratinocyte cancers and photosensitizing cardiovascular drugs. The aim of this study was to establish an association between cardiovascular drug use and the presence of AK.

METHODS

A total of 400 patients were enrolled into the study (200 with AK; 200 healthy persons in the control group). The group of patients with AK consisted of 106 women and 94 men (mean age 71 years). The control group included 102 women and 98 men (mean age 69 years). An analysis of the risk factors for developing actinic keratosis was performed in all patients with AK on the basis of a detailed, standardized interview.

RESULTS

The statistical analysis showed that features independently associated with increased risk of AK included: age > 80 years (OR 4.14; 95% CI 2.4-7.3), positive cancer history (OR 1.94; 95% CI 1.0-3.6), positive history of sunburns when < 18 years old (OR 2.18; 95% CI 1.3-3.7) and taking angiotensin-converting enzyme inhibitors (OR 2.28; 95% CI 1.2-4.3), angiotensin receptor AT1 blockers (OR 2.90; 95% CI 1.1-7.9) and calcium channel blockers (OR 2.4; 95% CI 1.0-5.3).

CONCLUSION

In conclusion, our study presented an association between cardiovascular drug use and the risk of developing AK.

Drug-induced photosensitivity: Photoallergic and phototoxic reactions

Drug-induced photosensitivity refers to the development of cutaneous disease due to the interaction between a given chemical agent and sunlight. Photosensitivity reactions can be classified as phototoxic or photoallergic. Sometimes, there is an overlap between these two patterns, making their distinction particularly difficult for the clinician. We review the drugs that have been implicated as photosensitizers, the involved mechanism, and their clinical presentations. The main topical agents that cause contact photosensitivity are the nonsteroidal antiinflammatory drugs, whereas the main systemic drugs inducing photosensitivity are antimicrobials, nonsteroidal antiinflammatory agents, and cardiovascular drugs. Drug-induced photosensitivity remains a common clinical problem and is often underdiagnosed.