<unk>  is an intensely pruritic dermatitis characterized by disseminated 1mm erythematous micropapules seen in a linear grouped arrangement secondary to Koebnerization due to patient scratching. It is caused by the ingestion of<unk><unk> s and was first described in 1977 by Nakamura. Although it is rarely seen outside of China and Japan due to a lower incidence of<unk>  consumption outside these regions, there is a well-established association between flagellate dermatitis and<unk><unk>  (Lentinula edodes) ingestion. Bleomycin ingestion may also cause similar findings. On physical exam, one key difference between the two is that post-inflammatory hyperpigmentation changes are usually seen with bleomycin-induced flagellate dermatitis and are not typically present with<unk><unk>  induced flagellate dermatitis. The median time of onset from ingestion of<unk><unk> s is typically 24 hours, ranging from 12 hours to 5 days. Most patients completely recover by 3 weeks, with or without treatment. Although the pathogenesis of<unk>  induced flagellate dermatitis is not clear, the theory most argued for is a toxic reaction to lentinan, a polysaccharide isolated from<unk><unk> s. However, Type I and Type IV allergic hypersensitivities have also been supported by the 24-hour median time of onset, clearance in 3–21 days, severe pruritus, benefit of steroids and antihistamines, and lack of grouped outbreaks in people exposed to shared meals containing<unk><unk> s. Most cases reported shortly after its discovery were due to consumption of raw<unk><unk> s, but several cases have since been reported after consumption of fully cooked<unk> s.
Shiitake mushroom dermatitis
Dermatitis repens
Granuloma faciale
African blackwood dermatitis
Blister beetle dermatitis
Lip licker's dermatitis
Ichthyosis bullosa of Siemens
Lichen myxedematosus