Skin Reaction to Sunlight Leads to Diagnosis of Boy’s Erythropoietic Protoporphyria
Physicians in Canada have reported the case of report of a 4-year-old boy whose delayed — and severe —reaction to sunlight led to a diagnosis of erythropoietic protoporphyria (EPP).
The case was described in the study “Delayed photosensitivity in a child with erythropoietic protoporphyria: a case report,” which was published in the SAGE Open Medical Case Reports.
The boy was referred to the hospital due to a history of photosensitivity since he was 18 months old.
The parents noticed that after sun exposure he would have swollen hands and violaceous eruptions (violet-colored, blistering) in both hands and ears, which were associated with considerable pain that often required morphine administration. These symptoms also could be accompanied by swelling on his face and mild redness on his nose, and more rarely by a rash on his ankles.
These skin symptoms would not manifest at the moment of sun exposure, but instead 20 minutes to four hours later. These episodes lasted for about 12 hours, after which time the symptoms would disappear without leaving scars, blisters, or noticeable marks.
Although the parents tried different sunscreens to prevent these symptoms, all products were ineffective.
Blood analysis revealed that he had levels of total protoporphyrin 24 times higher than normal, most of which was in the free-state circulating in the body. Zinc protoporphyrin level also was found to be elevated by more than three-fold.
Because protoporphyrin is a photosensitive molecule, when exposed to light, it can fluoresce (shine). Taking advantage of this feature, the researchers analyzed a blood sample by fluorescence scan with a microscope. This confirmed the presence of high levels of protoporphyrin in red blood cells.
The boy also presented low levels of iron, which is common among EPP patients. Levels of urinary porphyrin, antinuclear antibodies (ANA), and immune system complement levels were all within normal ranges, excluding the possibility of autoimmune disorders.
All the boy’s clinical parameters were consistent with the diagnosis of erythropoietic protoporphyria (EPP), the most common cutaneous porphyria in children. Still, researchers noted that in most EPP cases skin reactions occur while in the sun and not afterward, as happened in this case.
Since EPP is a genetic disorder, the researchers performed genetic testing. It revealed some alterations on the FECH gene that have been linked to severe defects on its coded protein and porphyria development.
There are limited treatment options for this disease, with prevention and reduction of skin to sunlight being the usual strategy.
The physicians recommended the boy use oral supplements of vitamin D, as some studies have indicated that EPP often is linked to vitamin D deficiency. He also started treatment with twice-daily Tagamet (cimetidine), which helped reduce the disease symptoms considerably.
“Our patient unfortunately was not referred to dermatology for evaluation in a timely manner as the delayed photosensitivity clouded EPP as a diagnosis,” the researchers wrote.
Still, treatment with Tagamet proved to be safe and effective to manage EPP symptoms. “Our patient and his family has had an improved quality of life that has been described by the mother as ‘truly life-changing’,” the researchers stated.
