Guinea pigs immunized with antibiotics (sodium cephalothin, CET) developed a systemic, delayed‐onset rash or so called generalized rash (GR) when challenged intraperitoneally with large amounts of CET seven weeks later. Skin test reactivity and GR intensity were most prominent at 24 hours. Microscopically, skin test reactions and flare‐up lesions of old skin test sites during GR were characterized by the onset of dermal infiltration of lymphocytes, striking dilatation and compaction of superficial venules at 24 hours, and papillary dermal infiltration of basophils at 48 hours. In addition, the animals that developed GR exhibited eosinophilia at 24 hours, which was followed by basophilia at 48 hours. GR developed with large doses of CET has properties similar to the so called SCBH designated by H.F. Dvorak. This experimental model may serve as a useful model for drug reactions in man which may involve SCBH.

Based on several reviews in Japanese dermatological journals. seventy-five cases of bacteriologically confirmed Mycobacterium marinum infection of the skin from 1969 through 1980 have been accumulated. These 75 cases accounted for 82% of all reponed cases of atypical mycobacterial infections of the skin in Japan (1).The following features were noted: Approximately half of the cases were occupationally related to fish handling; the other half occurred among fish tank hobby enthusiasts. The clinical presentation usually suggested sporotrichosis. with the majority of the skin eruptions appearing on the hand and 96 % being unilateral. Minocycline is recommended as the drug of choice.

Guinea pigs primed for delayed type hypersensitivity (DH) to antibiotics such as penicillin G (PCG), carbenicillin (CBPC), sulbenicillin (SBPC), ampicillin (ABPC), cephalexin (CEX), cephalothin (CET) and cephazolin (CEZ) by immunization in mycobacterial adjuvant developed a generalized rash (GR) and flare-up of previous test sites when challenged peritoneally with high doses of specific antigen. The GR was delayed in time, and histologically characterized by dilated and compacted small vessels and leucocytic infiltrations into the upper dermis. Animals immunized with CEX or CET developed a strong GR despite the absence of detectable antibodies.Hapten-carrier specificity and cross-reactivity in the GR system were essentially the same as those observed in skin testing of DH, but differed from those in the hemagglutination system. Accordingly, the GR shares many of the properties of DH skin test reactions: time course, histology, development despite an absence of detectable antibodies, carrier specificity, cross-reactivity. This experimentally induced rash may be a useful model for delayed type, generalized, exanthematic drug eruptions in man.

Three cases of sporotrichosis with numerous fungal elements were reported. Clinically these cases showed nodules to plaques with ulceration. Histologically, they showed unusual features, including histiocytic granuloma in the upper to middle dermis which contained few neutrophils but were surrounded by lymphocytes and epithelioid cells. There was no formation of an abscess. Fungal elements were found in abundance in the histiocytic granuloma, mainly in the form of oval or round spores of varying sizes, some of them produced germ tubes. No asteroid bodies were found. The spores stained positively with HE and PAS, and, in case 1, with anti‐Sporothrix schenckii antiserum. All three cases had been treated with topical corticosteroid ointment. In one case, after the topical corticosteroid treatment was stopped, the histological pattern returned to the usual features seen in sporotrichosis, and fungal elements decreased significantly. This unusual histological pattern was also observed in a specimen from a healthy control infected with Sporothrix schenckii and treated with steroid ointment. These histological and fungal patterns may be possibly induced by the local immunodeficiency following topical steroid treatment.

A sixty‐six‐year‐old woman has had numerous macules all over her body for a year without any systemic involvements. Plasma cells had infiltrated into the dermis and perivascular region, but showed no mitotic figures nor atypicalities. Laboratory examinations for Bence Jones protein, serum gammaglobulin, and immunoglobulins demonstrated no abnormal findings. The surface markers of the plasma cells were polyclonal; they were stained by anti IgA, IgG, IgM, kappa, and lambda. We consider this case not to be one of a true tumor but one of rather benign reactive proliferation of plasma cells in the skin, although its etiology is unclear.