170 An Introduction to Medical Mycology 



(a) Etiology.— While a number of writers have described this dis- 

 order as of fungous origin, few exact technical studies have been carried 

 out. Whalen stated that species of Monilia, Aspergillus, Penicillium and 

 Achorion may be found. He mentioned that in China and in the Americas 

 the predominating organism is a species of Aspergillus. In the Canal 

 Zone, however, Monilia is more often found. The question arises whether 

 these fungi, which are for the most part common laboratory "tramps" and 

 may be cultured from the surface of normal skin, can be incriminated as 

 the cause of the disease in question. The evidence so far offered is not 

 sufficient to prove beyond doubt that they can. It is possible that the spe- 

 cial conditions present in the external aural canal, particularly with retained 

 cerumen, also favor the proliferation of ordinary saprophytes, so that a path- 

 ogenic propensity is established. In our studies, Aspergillus has been a 

 common finding, but autoinoculation experiments on several occasions have 

 not been successful. If a species of Aspergillus is to be considered patho- 

 genic, it must be with the qualification that the site and the material present 

 are predisposing factors. We have cultured few fungi of recognized patho- 

 genic titer from this site. Streptococci have also been considered as possible 

 causative agents, since they are sometimes obtained on culture. We have 

 not noticed a common history of allergy in patients with otomycosis. No 

 age is exempt, although the majority of patients are young adults. Season 

 and climate have little effect on the course of the disorder. Swimming in 

 infected pools has been suggested as the origin of some characteristic in- 

 fections. 



(b) Symptoms.— The external ear around the meatus is swollen and red. 

 A moist mass of debris is usually present and may completely fill the canal. 

 When this is removed, the affected skin is seen to be exudative. If the con- 

 dition is mild or just beginning, the debris may be scanty, and at times it 

 is dry and flaky. While pruritus (worse at night) is present in almost every 

 case, evidence of trauma is rare. The disorder may extend down the canal 

 and affect the drum. It has been said that if the drum is perforated, the in- 

 fection may extend to the tympanic cavity and even invade the mastoid 

 cells. 



(c) Differential diagnosis.— Seborrheic eczema is rarely observed in 

 this site alone, so evidence should be sought on the scalp, behind the ears 

 and in other sites. The crusting has an oily character not present in otomy- 

 cosis. 



We are unable to differentiate this disorder from the exudative inflam- 

 matory disorder due to streptococci described by Mitchell as occurring on 

 the infra-auricular fold. 



Localized atopic eczema is of frequent occurrence and in this location 



