We agree with the editorial by Philip J. Rosenthal “Be Careful What You Eat!”1 and wish to highlight other foodstuffs which can have a deleterious impact on the health of returning travelers.
A 30-year-old woman attended our emergency clinic with a 2-day history of a widespread burning and pruritic rash following a trip to Hong Kong, where she had sustained multiple arthropod bites on the lower limbs. She had a history of well-controlled atopic dermatitis and, although she had witnessed the current public disorder, had had no direct contact with tear gas.
On examination, she was afebrile. There was a linear, erythematous, and slightly raised eruption on the torso and limbs (Figure 1), suggestive of scratch marks, with erythematous papules on the hands, legs, and feet. The face was spared. There was a patch of atopic dermatitis in each antecubital fossa, but no dermographism. There was no peripheral eosinophilia, C-reactive protein was normal, and HIV, syphilis, and antistreptolysin O serologies were negative.
The appearance of the rash caused us to take a detailed dietary history. She was a vegan and had eaten four skewers of shiitake mushrooms purchased from a street vendor approximately 48 hours before the onset of her symptoms. A diagnosis of shiitake mushroom dermatitis was made, and she was treated with oral prednisolone, 30 mg daily for 5 days, with complete resolution of her symptoms.
A flagellate rash following the recent ingestion of shiitake mushrooms (Lentinus edodes) is diagnostic.2 The dermatitis is a toxic reaction to a thermolabile polysaccharide, lentinan, which is present in raw and undercooked shiitake mushrooms.2 The rash can appear from two hours to five days following ingestion and may take up to 28 days to resolve.2 Severe cutaneous reactions have been reported.3
This case highlights the importance of a thorough dietary history in returning travelers with unexplained symptoms and that being “careful what you eat” is not restricted to raw or undercooked animal products.
Nguyen AH, Gonzaga MI, Lim VM, Adler MJ, Mitkov MV, Cappel MA, 2017. Clinical features of shiitake dermatitis: a systematic review. Int J Dermatol 56: 610–616.