Pressure Urticaria Can Mimic Physical Abuse

By Will Boggs MD

September 30, 2020

NEW YORK (Reuters Health) - Pressure urticaria in an infant can be misdiagnosed as physical abuse, according to a case report.

"While physicians and healthcare providers should be keen on screening for mistreatment, different presentations of skin disease can mimic abuse," said Dr. Allen F. Shih of Boston University School of Medicine, in Boston.

"Unfortunately, misdiagnosis can produce emotional trauma and a distrust of medicine in the affected family. Physicians should keep these considerations in mind and potentially err on the side of seeking additional medical input," he told Reuters Health by email.

Dr. Shih and Dr. Mohammed Sharaf described the case of a healthy Hispanic boy who was brought to primary care at the age of six weeks because of "bruises" on his arms and back that appeared several hours earlier. He was referred to the emergency department (ED).

Because the boy had also been brought to the ED at 4 weeks of age because of purplish bruising on both soles of the feet that had appeared eight hours earlier, the Department of Children and Families was granted emergency custody of the child.

Two days after admission, examination during a dermatology consultation revealed normal skin except for pink blanching patches on the upper back and linearly arranged pink blanching papules on the right lower leg at the site of his hospital identification band.

The identification band was removed, and by the next day the lesions had completely resolved without further intervention, the authors report in Pediatrics.

"It was most surprising that the skin markings completely disappeared by the next morning's examination, which confirmed that the rash was not a bruise," Dr. Shih said. "Typical bruising will take up to several weeks to fully resolve."

On the day following the initial consultation, the infant developed similar lesions on his soles five minutes after pushing his feet down onto a soft surface and tested positive for dermatographism. The skin changes were consistent with physical urticaria.

At the emergency court hearing, where the medical opinions of the dermatologist, pediatrician, and Child Protective Services concurred, the judge returned full custody of the child to his parents.

There were no skin findings on follow-up at six weeks.

"Because rashes are enormously diverse and can indicate various inflammatory, infectious, congenital, or other rare diseases, the dedicated training and experience of dermatologists are invaluable," Dr. Shih said. "Their expertise can drive diagnosis and treatment, ultimately allowing for the best care of the pediatric patient."

"Whether dermatology should be consulted earlier depends on the degree of clinical suspicion," he said. "If there is a story that seems a bit off from usual childhood trauma, I would recommend dermatology input sooner rather than later. I think that is why the pediatricians consulted the dermatologists in this case, because they thought something didn't add up."

Dr. Marcus Maurer of Charite - Universitaetsmedizin, in Berlin, who co-authored recent guidelines for the definition, classification, diagnosis, and management of urticaria, told Reuters Health by email that the case "shows that chronic inducible urticaria, including physical urticarias like delayed pressure urticaria, also occurs in children and very young children."

"The prevalence and relevance of these urticarias in children is underestimated, and awareness is low," he said. "More research and education are needed."

Dr. Mario A. Sanchez-Borges of Centro Medico Docente La Trinidad, in Caracas, Venezuela, who also co-authored the urticaria guidelines and recently reviewed diagnostic methods for physical urticaria, told Reuters Health by email, "Child abuse is frequent, and in cases of skin lesions of unknown etiology it should be considered."

"In this particular patient, although an effort was done to demonstrate abuse, neither medical experts nor the judge found any evidence of trauma suggesting child abuse," he said. "However, this possibility has to be kept in mind in patients with similar clinical pictures, especially in families with low socioeconomic level or poorly educated, as observed in suburbs of many American locations."

"Dermatographism can occur at any age, including newborns and very young children," Dr. Sanchez-Borges said. "The prognosis is excellent, with a tendency to disappear after a short time."

SOURCE: Pediatrics, online September 29, 2020.