Tumbleweed dermatitis.

Russian thistle (Salsola kali), the most common plant referred to as "tumbleweed" in the western United States, can cause a dermatitis in persons who come into direct contract with it. Tests were conducted to determine the mechanism of this dermatitis. Mechanical contact with plant branches, as well as scratch, patch, and photopatch tests with Russian thistle extract and scratch tests with 1.5% potassium nitrate, a plant constituent, were employed. These tests, along with transparent adhesive tape preparations and a skin biopsy, showed that in nonsensitized persons, dermatitis was due only to mechanical irritation of plant floral bracts. In sensitized individuals, Russian thistle floral bracts pierced the skin and stimulated an urticarial reaction.

Cheyletiella dermatitis.

A mild dermatitis probably due to Cheyletiella yasguri was observed in 2 persons whose pet dog was infested with this parasite. Cheyletiella mites differ morphologically from sarcoptic mites, which cause canine and human scabies. Treatment of man and dog with 1% gamma benzene hexachloride is usually successful in clearing this condition.

Apocrine cystadenoma of the penile shaft.

What is to our knowledge the first apocrine cystadenoma reported on the penile shaft is described. Of 96 previously reported apocrine cystadenomas, more than 90% were located on the face, ears, or scalp; the remainder occurred on the chest, axilla, or prepuce. Apocrine cystadenoma should be considered in the differential diagnosis of solitary blue, gray, or flesh-colored cystic nodules in those areas.