Clinical spectrum of porphyria cutanea tarda.

Correspondence: Giovanni Borroni, Clinica Dermatologica, IRCCS Policlinico S. Matteo, 27100 Pavia, Italy. Phone: international +39-0382-503494 – Fax. international +390382-526379. The term porphyria cutanea tarda (PCT) refers to a group of disorders biochemically charcaterized by reduced activity of uroporphyrinogen decarboxylase in liver and, in familial cases, in a number of tissues and cells including erythrocytes with subsequent accumulation of uroporphyrin and other porphyrins in organs and tissues.1,2 The presence of oxidized porphyrins in the skin adsorbing long ultraviolet and visible light, is responsible for the main clinical features of PCT. Clinically, PCT is a photosensitivity disorder without the neurologic signs of precursor porphyrias diseases.3 The most common variety of PCT is the sporadic or acquired form in which there is a predisposition to acquire the liver enzymatic defect which develops in response to different triggering exogenous factors. The patients are usually adults and they have no family history of PCT.4 The most frequent factor implicated in precipitation and aggravation of PCT is ethanol, although only a few alcoholics with chronic liver damage develop PCT. Other common exacerbating factors are therapeutic estrogenic hormones, different drugs (griseofulvin, vitamin B12, sulphonamides, barbiturates, hydantoins), iron excess, viral infections (such as hepatitis B and C viruses, HIV infection), and all factors affecting liver function PCT has also been associated with chronic renal failure, long-term hemodialysis, diabetes mellitus, and, more rarely, with other systemic diseases.4 Acute attacks of PCT are not common, while a history of chronic photosensitivity is usual. Liver involvement is always present even if clinical manifestations are not evident. Urinary porphyrin assays are increased and it is possible to observe pink-red fluorescence with a Wood’s lamp (Figure 1).