Adler, Michael J.

SummaryShiitake 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.