<unk>  is primarily caused by an acquired bacterial infection of the epiglottis. Historically it was most often caused by Haemophilus influenzae type B, but with the availability of immunization this is no longer the case. Presently the bacteria most often causing infection are Streptococcus pneumoniae, Streptococcus pyogenes, or Staphylococcus aureus. Alternate risk factors and causes associated with infection include burns and other trauma to the area. Medical research has also identified a link between<unk>  and crack cocaine usage. Underlying health afflictions, such as Graft-versus-host disease and Lymphoproliferative disorders, have also been identified as contributors of increased risk for developing the infection . This is in part caused by the host's decreased immune response coupled with the common sites targeting the soft tissue of the lymphatic system, both of which are already negatively impacted by the pre-existing illnesses.
Epiglottitis
Pharyngitis
Adenoiditis
Croup
Nasal vestibulitis
Laryngitis
Parapharyngeal abscess
Streptococcal pharyngitis