The fungus Paecilomyces lilacinus is most frequently encountered as an opportunistic pathogen in immunosuppressed patients.

This organism has been associated with a wide variety of infections. Clinical symptoms can be nonspecific, and it is not usually possible to distinguish infection due to Paecilomyces from infection caused by other fungal organisms based on physical exam alone. When the organism is identified in nonsterile sites, distinguishing colonization from active infection can be difficult.

Paecilomyces can be isolated from many environments but is most commonly found in soil and sewage, although it has been isolated from saunas and in laboratories (airborne contaminant) as well.

Skin manifestations include plaques, nodules, or pustular lesions. Lesions may be solitary or disseminated. A sporotrichoid pattern can be seen. Cellulitis has also been reported. This organism has caused sternal wound infections, sinus infections, and osteomyelitis.

Especially devastating is infection of ocular structures, with cases of keratitis and endophthalmitis reported. Very poor outcomes with this infection are common, including enucleation of the affected eye and loss of vision. A history of intraocular lens implantation and recent steroid use are risk factors for this infection.