Cutaneous photosensitivity diseases induced by exogenous agents

Area of Science:

• Dermatology
• Toxicology
• Immunology

Background:

• Cutaneous photosensitivity encompasses idiopathic, endogenous, and exogenous causes.
• Exogenous photosensitivity includes phototoxicity, photoallergy, and systemic disorders with photosensitivity.
• Phototoxic reactions are common, while photoallergic reactions are less frequent, with both often linked to UVA radiation.

Purpose of the Study:

• To differentiate between phototoxic and photoallergic reactions.
• To identify common exogenous agents causing photosensitivity.
• To outline the clinical characteristics, diagnosis, and management of photosensitivity disorders.

Main Methods:

• Review of literature on cutaneous photosensitivity.
• Analysis of causative agents for phototoxic and photoallergic reactions.
• Comparison of pathogenesis, clinical features, and diagnostic approaches.

Main Results:

• Phototoxic reactions are more common than photoallergic reactions.
• Common phototoxic agents include psoralens, porphyrins, coal tar, antibiotics, and NSAIDs.
• Common photoallergic agents include topical antimicrobials, fragrances, sunscreens, NSAIDs, plants, and psychiatric drugs.
• Drug-induced systemic diseases like lupus erythematosus, porphyria, and pellagra can manifest with photosensitivity.

Conclusions:

• Distinguishing between phototoxic and photoallergic reactions is essential for effective patient management.
• A wide range of exogenous substances can induce photosensitivity through phototoxic or photoallergic mechanisms.
• Photosensitivity can be a key feature of drug-induced systemic conditions.