Diagnosis:Recurrent Group A Streptococcus Infection With Vasculitis
TORONTO The differential diagnosis included leukocytoclastic vasculitis, but that condition is rare, with no clear reports in the literature. Polyarteritis nodosa was also considered, although this patient did not have the painful, tender nodules that are often associated with this condition.
The cutaneous form of polyarteritis nodosa (cPAN) primarily affects the skin without systemic involvement such as vasculitis. Microscopic PAN (mPAN), in contrast, often affects small arteries and veins and can feature lung and kidney involvement. "These are different conditions, but they may be part of a spectrumfrom mPAN to PAN," Dr. Miriam Weinstein said at the annual conference of the Canadian Dermatology Association.
A skin biopsy in this case indicated neutrophilic vasculitis with inflammation.
"Group A strep was cultured from his throat when I saw him on the tenth eruption," Dr. Weinstein said. His throat swab findings were negative between episodes.
Can group A strep be seen with vasculitis? "The answer is 'yes'," said Dr. Wein-stein, medical director of the pediatric dermatology fellowship program at the Hospital for Sick Children in Toronto.
Of the different PAN subtypes, cPAN is the only one consistently linked with group A streptococci infection in the literature (Int. J. Dermatol. 1998;37:664-6; Arch. Dis. Child. 1996;74:367; and Ann. Rheum. Dis. 1995;54:134-6).
Determination of the precise diagnosis was challenging. "He had a recurrent strep infection. This case involved urticarial eruption, which is uncommon with strep. He also had some features consistent with mPAN … vasculitis of small to medium arteries," Dr. Weinstein said.
The final diagnosis was group A β-hemolytic streptococci-induced mPAN with urticarial lesions.
Recurrent strep infections also can affect younger children, although the presentation can differ. "If you see persistent erythematous folds, particularly in infants and babies, think group A strep and swab," she suggested.
Group A strep infection is often mistaken for Candida, irritant contact dermatitis, or seborrheic dermatitis. It is often treated but persists, Dr. Weinstein said. Frequently there is an odor with group A strep infection that is not present with Candida. "Don't forget perianal strep. It is more common than reported and often missed," she said. This usually affects patients younger than 10 years. If asked, these kids will have a history of painful bowel movements and perianal itch. "Often the parents don't know about this. It is the first time it's asked," she noted.
Both Candida and group A strep can induce psoriasis. Psoriasiform infectious disease features widespread, acute, well-demarcated, and erythematous plaques with scale. "There are no reports of this in the literature, but many pediatric dermatologists see this," Dr. Weinstein said.
The child had an occurrence of urticarial eruptions, which is uncommon with strep. Courtesy Dr. Miriam Weinstein