We examined the skin samples from 23 fattened pigs with papular dermatitis (PD) and from 17 pigs showing no skin lesions; the live weight of the pigs was from 95 to 105 kg and the pigs came from a large fattening house D that is located in the region where the mines are frequent (lignite extraction). It was only in 26% of pigs with PD where the common ectoparasites Haematopinus suis and Sarcoptes scabiei var. suis were found out. The skin lesions were not fluorescent in the light of Wood's lamp. The fungi Aspergillus flavus, A. fumigatus, A. tereus, Chrysosporium, Mucor sp., Scopulariopsis sp. were sporadically isolated from the skin lesions in 39% of pigs with PD. In 65% of pigs with PD Staphylococcus aureus was isolated from the skin lesions, which was not found in pigs without dermal lesions. Staphylococcus epidermidis was isolated in 87% of pigs with PD and 58% of pigs without any skin changes. The skin lesions were virus-free. Increased concentrations of cadmium and mercury were observed in the skin of pigs with PD and in control pigs. The concentration of aflatoxin B1 in the skin of the two groups of pigs did not exceed the level of 5 micrograms X kg-1, in PD pigs it was, however, twice higher than in the clinically healthy pigs. The residues of chlorinated hydrocarbons in the subcutaneous fat were not higher than the certified hygienic levels. Both epidermis and corium are affected by inflammatory lesions. At the beginning, neutrophil infiltration with necrotization of epithelial cells prevails. It is followed by capillary proliferation with angioblast and fibroblast multiplication and straggled lymphoid infiltration. It is necessary to distinguish by differential diagnostics: swine pox, parakeratosis of swine, lesions of impetigo contagiosa suum, pustular dermatitis and scab of swine, and from rarely occurring skin diseases of swine hypotrichosis cystica suis and demodicosis of swine. No conclusions can be drawn explicitly on the etiology and pathogenesis of papular dermatitis in fattened pigs. We must study the potential interactions of negative environmental factors with regulating homeostatic and adaptation mechanisms in fattened pigs.