Severe cutaneous infections in leukaemic patients are difficult to treat and can rapidly become fatal. We report on a case of essential thrombocythemia evolved to a myelodysplastic syndrome and finally, to an overt myeloid leukaemia, refractory to chemotherapy. In the presence of a marked neutropenia, the patients developed a wide Staphylococcus epidermidis necrotising dermatitis. The diagnosis was made possible only by a skin biopsy culture and the antibiotic treatment, based on antimicrobial susceptibility tests, rapidly resolved the infection. In neutropenic patients, appropriate laboratory tests and treatment, can lead to recovery of life-threatening infections.