Phototoxicity and photoallergy
| Autor: | John H. Epstein |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
medicine.medical_specialty
Photosensitizing Agents Erythema business.industry Dermatitis Photoallergic Solar urticaria Dermatology Photosensitizing Agent medicine.disease Pseudoporphyria Diagnosis Differential chemistry.chemical_compound Photosensitivity chemistry Dyschromia Medicine Humans Surgery medicine.symptom business Phototoxicity Psoralen Dermatitis Phototoxic |
| Zdroj: | Seminars in cutaneous medicine and surgery. 18(4) |
| ISSN: | 1085-5629 |
| Popis: | Photosensitivity may be phototoxic or photoallergic. Phototoxicity is much more common. There are 2 types of phototoxicity: photodynamic, which requires oxygen, and nonphotodynamic, which does not. Reactions induced by porphyrin molecules, coal tar derivatives, and many drugs are photodynamic. The reaction induced by psoralens, for the most part, is nonphotodynamic. Acute phototoxic reactions are characterized by erythema and edema followed by hyperpigmentation. Long-term ultraviolet phototoxicity results in chronic sun damage and skin cancer formation. Also, certain chemicals such as psoralen molecules and coal tar are photocarcinogenic. Phototoxic reactions to certain drugs produce unusual clinical patterns, that is lichenoid eruptions, dyschromia, photo-onycholysis, and pseudoporphyria. Photoallergy is an uncommon acquired altered reactivity dependent on an immediate antibody or a delayed cell mediated reaction. Solar urticaria is an example of the former, whereas photoallergy to exogenous chemicals is an example of the latter. Photoallergy to systemic drugs does occur but is difficult to characterize. The action spectrum for photoreactions to exogenous agents usually at least includes the ultraviolet A rays for both phototoxicity and photoallergy. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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