Reactive and Infective Dermatoses Associated with Adult-Onset Immunodeficiency due to Anti-Interferon-Gamma Autoantibody: Sweet's Syndrome and Beyond

Immunodeficiency due to anti-interferon-gamma autoantibody (anti-IFN-&#947; autoAb) is an emerging adult-onset immunodeficiency syndrome predominantly found in Southeast Asians. It is associated with severe or disseminated infections caused by non-tuberculous mycobacteria (NTM) and other opportunistic pathogens. We describe 3 patients with anti-IFN-&#947; autoAb who developed reactive and infective dermatoses, and thoroughly review the existing literature on dermatoses associated with the immunodeficiency syndrome. Case 1 developed Sweet's syndrome associated with <i>Mycobacterium chelonae</i> lymphadenitis and penicilliosis. Case 2 suffered from multiple episodes of lobular panniculitis during recurrent infections by NTM, <i>Penicillium marneffei</i> and <i>Burkholderia pseudomallei</i>. Both cases responded to immunomodulating agents including corticosteroid and non-steroidal anti-inflammatory drugs. Case 3 had direct skin invasion by <i>M. chelonae</i> and responded to prolonged anti-mycobacterial therapy. A novel working algorithm is proposed for the diagnosis and treatment of these patients who may be encountered by the dermatologist and histopathologist in clinical practice.