Novel Treatment Using Cimetidine for Erythropoietic Protoporphyria in Children.

IMPORTANCE

Erythropoietic protoporphyria (EPP) is a rare hereditary disease of heme biosynthesis that manifests as severe photosensitivity and hepatotoxicity. There have been no effective treatments to date. Cimetidine has been shown to inhibit heme biosynthesis and results in symptomatic improvement in patients with acute intermittent porphyria (AIP) and porphyria cutanea tarda (PCT). There is only 1 report in the literature describing the use of cimetidine in the effective treatment of an adult patient with EPP.

OBJECTIVE

To describe the successful use of cimetidine in pediatric patients with EPP.

DESIGN, SETTING, AND

PARTICIPANTS

Retrospective medical record review carried out in a pediatric dermatology practice at an academic institution of patients diagnosed with EPP who were younger than 18 years and treated with systemic cimetidine in the past 3 years.

INTERVENTIONS: Systemic cimetidine.

MAIN OUTCOMES AND MEASURES: Resolution of skin photodamage was evaluated on clinical examination. Subjective measures including tolerability to sun exposure, ability to participate in outdoor activities, and objective evaluation including serum erythrocyte protoporphyrin levels and liver function tests following treatment were assessed.

RESULTS

All 3 cases reported a rapid reduction in photosensitivity within weeks following initiation of systemic therapy. Their skin photodamage were also improved or resolved completely on subsequent examination. Laboratory study results also revealed reduction in serum erythrocyte protoporphyrin levels and improved liver function. None of the patients have reported any adverse effects of the systemic treatment after more than 2 years of treatment.

CONCLUSIONS AND RELEVANCE: Children with EPP currently have limited therapeutic options and experience substantial disease impact on their quality of life. This is the first case series demonstrating that cimetidine, a readily available oral medication, can be a promising treatment for children with EPP.