Clinical features of shiitake dermatitis: a systematic review.

Shiitake dermatitis is a rare cutaneous reaction to lentinan, a polysaccharide component in the cell walls of shiitake mushrooms (Lentinula edodes). Herein, we systematically review the case report and case series English-language literature on shiitake dermatitis, which refers to a total of 50 patients (38 males, 12 females; mean age: 44.58 years). The majority of cases occurred after the consumption of raw mushrooms, whereas 22% of cases were caused by the eating of lightly or undercooked mushrooms. The most common clinical presentations, localized symptoms, and systemic findings include linear flagellated dermatitis (98%), pruritus (78%), and fever, diarrhea, and mucosal ulcers, respectively. The diagnosis of this entity continues to be based on clinical findings as laboratory abnormalities, and the findings of skin biopsies and patch/prick tests are nonspecific and inconsistent. The condition is self-limiting, resolving in approximately 12.5 d without treatment. Based on the included case reports, it appears that medical treatment may slightly shorten the course of disease (to 9-11 d, varying by therapy) but should be considered on an individual patient basis. However, the treatment of symptoms, reassurance, and the avoidance of re-exposure are sufficient treatment recommendations for this condition.