Shiitake dermatitis in a 5-year old boy: First pediatric case report

Abstract

Shiitake mushrooms are increasingly being consumed in the West because of their possible health benefits and changing dietarypreferences. A rare but increasingly occurring undesired effect caused by the thermolabile polysaccharide lentinan in the Shiitakemushroom is the incidence of a particular toxic dermatitis called flagellate dermatitis or Shiitake dermatitis. This dermatitis isextremely pruritous, heals without scarring in one to eight weeks and the effect of treatment is doubtful. The pathogenesis has notbeen completely explained and it is unclear why some people react more than others. We here present what we believe to be thefirst pediatric case of Shiitake dermatitis in a 5-year-old boy.

A Culinary Misadventure: A Case Report of Shiitake Dermatitis

“…8,9 Although the exact pathophysiology is unclear, the rash is thought to be due to a toxic reaction to lentinan, a polysaccharide component of the mushroom that stimulates interleukin-1 which results in vasodilation and inflammation. 6,7,10 In fact, a similar cutaneous eruption has been observed in a select few patients undergoing chemotherapy treatment with lentinan. 2 Because lentinan is denaturized around 130-145 degrees Celsius, it has been suggested that only exposure to raw or undercooked mushrooms would cause the dermatitis.…”

“…2 Characterized by linear, erythematous papules resembling lashes from a whip, it is described as a flagellate dermatitis -a name derived from the Flagellants, a medieval religious sect whose members would whip themselves as a demonstration of their faith. 6,7 The lesions typically appear 24 to 48 hours after consumption of the mushroom 2 and almost always involve the trunk, commonly involve the limbs, less commonly involve the face and neck, and rarely involve the hands and feet. 8 Although the lesions may rarely present as petechiae, purpura, plaques, pustules, and even morbilliform, the notable flagellate lesions appear in nearly all cases.…”

“…2 Because lentinan is denaturized around 130-145 degrees Celsius, it has been suggested that only exposure to raw or undercooked mushrooms would cause the dermatitis. 2,3,6 In one report, a patch test using mushrooms cooked at 100 degrees Celsius resulted in the skin eruption but not when the mushrooms were cooked at 150 degrees Celsius. 11 However, there have also been multiple cases of shiitake dermatitis after the consumption of cooked mushrooms 5,7 and even after drinking a beverage containing shiitake mushroom extract.…”

“…5 There is some debate as to whether shiitake dermatitis is truly the result of a toxic reaction. 3,[6][7][8] A few studies have demonstrated that certain human leukocyte antigen alleles and cytokine profiles make individuals more susceptible to generating a skin reaction when exposed to antigens, and an argument could be made that a similar connection could explain shiitake dermatitis although a specific marker has yet to be identified. 6,8 There is also some evidence that a T-cell reaction could also be the root of the rash.…”

“…4 Most episodes occurred in Asia, and although there have now been several cases in Europe and the Americas, it is still a relatively extraordinary occurrence in Western countries and the United States. 5,6 Below, we present a case of a young female presenting to the emergency department with shiitake dermatitis.…”