PMID: 2488874Jan 1, 1989Paper

Mechanisms of phototoxicity in porphyria cutanea tarda and erythropoietic protoporphyria

Immunology Series
H W Lim

Abstract

The porphyrias are the only group of diseases caused by endogenous phototoxic agents. While patients with erythropoietic protoporphyria and those with porphyria cutanea tarda both have skin lesions on sun-exposed areas, there are differences in their cutaneous manifestations. Based on information discussed in this chapter, the following pathophysiologic mechanisms can be proposed. In porphyria cutanea tarda, photoactivation of the complement system in the presence of uroporphyrin results in activation of dermal mast cells, which release their proteases. This results in dermal-epidermal separation, reflected clinically as skin fragility and vesicles. The interaction between activated mast cells with fibroblasts, the nature of which is still unclear, may contribute to fibrosis and sclerodermoid skin changes. The stimulatory effect of uroporphyrin on collagen biosynthesis by fibroblasts, which occurs independent of irradiation, may be responsible for the sclerodermoid lesions seen at sun-exposed as well as sun-protected areas. In erythropoietic protoporphyria, mast cell activation can occur as the result of complement activation induced by protoporphyrin and irradiation. Protoporphyrin and irradiation may also directly induce the ...Continue Reading

Related Concepts

Related Feeds

Anxiety Disorders

Discover the latest research on anxiety disorders including agoraphobia, panic disorder, obsessive-compulsive disorder, and post-traumatic stress disorder here.

Anemia

Anemia develops when your blood lacks enough healthy red blood cells. Anemia of inflammation (AI, also called anemia of chronic disease) is a common, typically normocytic, normochromic anemia that is caused by an underlying inflammatory disease. Here is the latest research on anemia.

© 2022 Meta ULC. All rights reserved