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Erythropoietic Protoporphyria Looked Autoimmune at First


 

CORONADO, CALIF. — It is a wise rheumatologist who knows when to refer a child to a dermatologist, judging from cases reported at the annual meeting of the Pacific Dermatologic Association. Dr. Anna L. Bruckner discussed two such cases.

The first was that of a 9-year-old girl who was referred by a rheumatologist for evaluation of possible dermatomyositis.

The girl had a 4-month history of intermittent redness and swelling of the hands that worsened after prolonged outdoor activities.

The girl was healthy and described one remote episode of burning hands following a hike several years before. She was on naproxen and ranitidine, which had been prescribed by the rheumatologist as treatment for the redness and swelling.

“The work-up by the rheumatologist was negative for autoimmune disease,” said Dr. Bruckner.

Clinical exam revealed a few waxy papules and plaques distributed over the knuckles. Her hands also had a slightly weather-beaten appearance. A skin biopsy showed cuffs of hyaline material around the superficial blood vessels in the upper dermis, suggesting a diagnosis of erythropoietic protoporphyria (EPP). Confirmatory studies demonstrated that the patient had elevated total red blood cell porphyrins with a predominance of free protoporphyrin.

EPP is the most common type of porphyria in children. It presents between 1 and 6 years of age and symptoms include burning, stinging, redness, and edema, all of which occur following sun exposure.

The condition is caused by a deficiency of ferrochelatase, which leads to accumulation of protoporphyrin IX.

Treatment involves sun avoidance, sunscreens, and beta-carotene 30–150 mg/day.

In the second case, a 6-year-old girl with suspected loose anagen syndrome was referred to Dr. Bruckner, who is director of pediatric dermatology at Lucile Packard Children's Hospital in Palo Alto, Calif. In this condition, the anagen hairs are loosely anchored into the scalp so that the hair will fall out with very minor trauma. The hair is short, sparse, and seldom cut. It typically is seen in blond girls aged 2–5 years, but can affect boys and brunettes as well.

Many of the girl's friends at school “had long, flowing hair and she wanted to see if there was something we could do about her hair,” Dr. Bruckner said. She did a gentle hair pull test and only two hairs came out. The girl's hair was very short and had a matted appearance in the back.

Dr. Bruckner prescribed 5% minoxidil lotion and scheduled a 3-month follow-up visit. On follow-up the girl's hair was fuller but it remained short and gentle hair pull tests remained negative.

“We obtained some additional history,” Dr. Bruckner recalled. “Her nails were thin, often peeled, and never required trimming. She had no history of dental anomalies, and she'd had a coarse, deep voice since age 2. Her mother said that she looked different than her siblings.”

She also had sparse lateral eyebrows, a pear-shaped nose, and a thin upper lip.

The girl's combination of short, sparse hair and abnormal facial features led Dr. Bruckner to consider trichorhinophalangeal syndrome (TRPS) type 1 as the diagnosis.

An x-ray of the girl's hand performed after her follow-up visit revealed cone-shaped epiphyses of the phalanges, which confirmed the diagnosis. TRPS type 1 is an autosomal dominant disorder characterized by craniofacial and bony abnormalities that include sparse, slow-growing hair and thin lateral eyebrows, a pear-shaped nose, elongated philtrum and thin upper lip, prominent ears, and cone-shaped epiphyses of the phalanges.

Variable findings include short stature (the patient was in the 25th percentile for height), nail abnormalities, teeth abnormalities, and a deep voice. The condition is caused by mutations in the TRPS1 gene.

Although there is no specific treatment for TRPS type 1, the girl's parents were happy to better understand why their daughter's hair failed to grow normally. She has continued to use 5% minoxidil for 6 months with some improvement.

Variable findings of TRPS type 1 include short stature, nail and/or teeth abnormalities, and a deep voice. DR. BRUCKNER

Waxy papules and plaques are shown on a girl with erythropoietic protoporphyria. Courtesy Dr. Anna L. Bruckner

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