What causes photosensitivity rash?

Many causes. Causes for photosensitivity) can be classified into 1) those caused by the presence of an underlying skin condition (eg., lupus); 2) chemicals/drugs topical or ingested which are photosensitizers (eg., tetracyclines, dyes); 3) genetic diseases (eg., xeroderma pigmentosa); 4) metabolic disorders (porphyrias) and 5) idiopathic (unknown).

Related Questions

What is the definition or description of: Photosensitivity rash?

Ultraviolet light. Photsensitivity (PS) refers to the inflammation that results from the interaction of UVL with the immune response. There are a variety of causes: medications (topical or systemic), immune disorders (e.g. Lupus), and metabolic or syndromic. PS is distinguished from phototoxicity (sunburn). Read more...