Calcinosis cutis secondary to percutaneous penetration of calcium chloride in dogs

Accidental exposure of the skin of a dog to a commercial hygroscopic landscaping product (77-80% CaCl2) caused contact-irritant dermatitis within 24 hours. Papules and eroded to ulcerated plaques with hyperproliferative margins developed on various areas of the skin that had come in contact with CaCl2. Histopathologic findings were typical of calcinosis cutis. Reproducible lesions similar to those observed on the referred dog were induced on 5 clinically normal dogs exposed to small amounts of the compound. Histopathologic documentation of the percutaneous penetration of CaCl2, with evidence of calcinosis cutis, was found in the dogs as early as 24 hours after continuous skin contact with the offending substance. Electron-microscopic evidence of crystalline deposits within dermal collagen also was found in skin biopsy specimens obtained 24 hours after contact with CaCl2. Serum calcium and phosphorus concentrations in the 5 dogs remained within normal limits before and after topical application of CaCl2.