[Cross allergies following sensitization with dinitrochlorbenzol (DNCB)].

82 of 203 patients with malignant melanoma and other skin diseases suitable for DNCB-immunotherapy were re-exposed to standard test substances, chloramphenicol, and another four p-nitrocompounds similar to DNCB by epicutaneous patch tests 6-15 months after primary sensitization with DNCB. The DNCB sensitizaton threshold proved to be unchange. No cross allergy with chloramphenicol was observed However, two patients showed sensitization against picric acid not seen before. A group allergy may be suggested in both cases. Immunotherapy with DNCB is briefly discussed. Apart from a very low rate of group sensitization, topical treatment with threshold concentrations of DNCB has neither toxic effect nor produces scarring nor generalized eczema.