Porphyrias

Porphyrias are metabolic disorders of heme synthesis. Partial enzyme deficiencies result in excessive accumulation and excretion of 5-aminolevulinic acid, porphyrins and porfobilinogenului. Porphyria cutanea tarda porphyria is most commonly found in Europe and North America. Bullous photosensitivity Pseudoporfiria describe a physically and clinically mimicking porphyria cutanea tarda.
Porphyria cutanea tarda is caused by deficiency of an enzyme of heme biosynthesis. Porphyrins accumulate in the liver, are transported in plasma and excreted in urine. Sun exposure of these patients to determine the fragility of skin, blisters, bubbles, hypertrichosis, hypopigmentation, scleroderma changes, dystrophic calcifications, milia and scarring. In porphyrins pseudoporfirie no abnormalities. The skin lesions can not be distinguished from those of porphyria cutanea tarda. Pseudoporfiria has been reported in hemodialysis patients with excessive exposure to ultraviolet A.
Pseudoporfiriei are numerous causes including exposure to ultraviolet A, hemodialysis, some drugs, vitiligo. The main treatment is discontinuation of medication pseudoporfiriei if this is possible. Clinical resolution may require several months, especially in drug-induced form. The prognosis is good once you removed pseudoporfirie triggering agent.
Pathogenesis
Pathologie pseudoporfiriei precise mechanism is unknown. It impugned the role of visible light or ultraviolet A drug-induced fit. It turns out that fotosensibilizatorii are deposited along the endothelium of blood vessels in affected skin. Triggered an immune response against antigens is believed to develop after exposure to light of the dermis. It is considered that damages the endothelium by elberarea fotosensibilizantii exogenous protease after exposure to the sun. Then immunoglobulin G binds to altered endothelium result in the formation of bubbles in the lamina lucid.Pseudoporfiriei pathogenesis caused by hemodialysis is considered to be due to aluminum hydroxide. This solution is found in hemodialysis and cause similar diseases porphyrias after long term administration.
Causes and Risk FactorsPseudoporfiriile can be produced by various drugs, excessive sun exposure and hemodialysis.
Medicines that may cause pseudoporfirie include:-Naproxen, ketoprofen, nabumetone, oxaprozin, mefenamic acid, rofecoxibNalidixic acid, tetracycline, ampicillin-sulbactam, cefepime, ciprofloxacin-Voriconazole, furosemic, butamida, triamterene, hydrochlorothiazide, torsemida, bumetamida-Amiodarone, 5-fluorouracil, imatinib, cyclosporine, dapsone, pyridoxine-Etretinat, isotretinoin, aspirin, flutamide, cola, ultraviolet A, oral contraceptivesUV-B phototherapy, hemodialysis, vitiligo.
Signs and symptoms
A careful history is important to detect cases of exogenous pseudoporfiriei. Pseudoporfiria clinically characterized by increased fragility of skin, redness and appearance of bubbles in the blood and erosions on sun-exposed skin, identical to those seen in patients with porphyria cutanea tarda. Hypertrichosis, hyperpigmentation and scleroderma changes found in porphyria cutanea tarda are not observed in pseudoporfirie.Pseudoporfiria which is clinically similar to erythropoietic protoporfiria is described only in children who have juvenile rheumatoid arthritis naproxen.
Diagnosis
Laboratory studies:-The most important test is to evaluate serum porphyrin, which is negative if the patient has no real porphyriaOther causes of photosensitivity, which must be excluded by obtaining connective tissue disease antinuclear antibody, antiRo, ribonucleoproteina Smith, antiADN.The differential diagnosis is made with the following disorders: bullous pemphigoid, epidermolysis bullosa, protoporfiria erythropoietic, lupus erythematosus, porphyria cutanea tarda.
Treatment
In drug-induced pseudoporfiriei it to the interruption of drug therapy trigger. Resolution of signs require a few months.