however, the porphyrin photosensitization is not the primary cause, as many patients on dialysis in a similar manner were slight increases in plasma levels of porphyrin and do not develop lesions bulb.

This is all lower case. Can you fix that?
However, the porphyrin photosensitization is not the primary cause, as many patients on dialysis in a similar manner were slight increases in plasma levels of porphyrin and do not develop lesions bulb.