Clinical presentations of opportunistic infections in AIDS patients have dramatically changed since the introduction of HAART. The immune reconstitution syndrome (IRS) is typical of this change. The authors discuss the case of an AIDS female patient presenting with subcutaneous abcesses and abdominal lymph node enlargement due to Mycobacterium avium and occurring 10 weeks after initiation of HAART. This was related to the exacerbation of immune response against the bacteria that had previously infected the patient. Many cases of IRS involving M. avium have now been described, but cutaneous localisations remain infrequent. The treatment consists in HAART continuation associated with anti mycobacterial antibiotics and possibly anti inflammatory drugs.