Pseudoporphyria Treatment & Management

Updated: May 11, 2018
  • Author: Vineet Mishra, MD, FAAD; Chief Editor: Dirk M Elston, MD  more...
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Treatment

Medical Care

The primary treatment of pseudoporphyria is to discontinue the offending agent whenever possible. This may be facilitated by substituting certain medications (eg, tolmetin instead of naproxen for juvenile rheumatoid arthritis, nonthiazide agents for hypertension, nilotinib or dasatinib for imatinib in the setting of chronic myeloid leukemia) for alternative agents that have not been associated with pseudoporphyria. [6, 68, 75, 76] In cases in which substitution or discontinuation is not possible, sun protection has been successfully used as both therapy and prophylaxis against recurrent eruptions. [69, 77, 78] Patients should be adequately educated on this topic. [69] Patients should be adequately educated and counseled to avoid direct sun exposure, wear sun-protective clothing, and apply titanium oxide‒ or zinc oxide‒based sunscreens, which are resistant to wavelengths known to induce porphyric eruptions (400-440 nm). [69] Resolution of the clinical findings may take many months, particularly in drug-induced pseudoporphyria.

In addition to discontinuation of causative agents, some substances have been used in the treatment of pseudoporphyria. N-acetylcysteine (a glutathione precursor) has been reported to improve both dialyzed and nondialyzed forms of chronic renal disease associated pseudoporphyria. [6, 70, 79, 80, 81, 82] Proponents of this therapy have proposed that patients on hemodialysis have decreased levels of glutathione,4,5 (an antioxidant) and that reactive oxygen species may contribute to skin damage. [80] One case series involving two patients with pseudoporphyria demonstrated rapid healing of lesions in both patients after the introduction of N-acetylcysteine (with one patient receiving 200 mg four times daily and the other 600 mg twice daily) to treatment, which was otherwise unchanged. [80] It was also noted that discontinuation of the medication in one patient led to a recurrence of blistering. Additional case reports note resolution of blistering after 8 weeks of treatment with dosages of N-acetylcysteine ranging from 600-1200 mg daily. [70, 81] Further investigations evaluating the efficacy are needed to confirm results. However, oral N-acetylcysteine has few, mild adverse effects consisting of nausea, vomiting, and diarrhea and has been suggested to be a safe therapeutic option for pseudoporphyria. [80, 70, 81]

Despite the reported success of N-acetylcysteine, there are cases that demonstrate resistance to this agent. [73, 83] Alternatives that have been documented in the literature include the use of the antimalarials chloroquine and hydroxychloroquine. [82, 83] A case report of pseudoporphyria that was resistant to N-acetylcysteine was noted to have complete resolution after 200 mg of chloroquine administered weekly for 1 month. [83] Improvement in lesions of pseudoporphyria have also been noted with 2 months of daily administration of 10 g of oral glutamine, a nonessential amino acid. [84] This therapy was reportedly well-tolerated with no adverse effects and may be an alternative treatment for cases of pseudoporphyria that are resistant to either N-acetylcysteine or chloroquine. Other case reports have reported improvement with daily administration of 5 mg beta-carotene and 50 mg of green tea extract. [43, 80]