182 An Introduction to Medical Mycology 



cytes, lymphocytes, plasma cells and eosinophils. Surrounding them is a 

 variable amount of cellular detritus and granulation tissue. The ray fungus 

 is described further on pages 320 and 323. As the lesion increases in size, 

 the central purulent area becomes larger, and finally the pus pushes 

 through normal tissue. Granulation tissue or, in later stages, scar tissue 

 may be the only pathologic finding and granules may not be found. The 

 final outcome is the development of sinus tracts leading to the surface of 

 the skin or to a cavity within the body. 



(e) Immune reactions.— It was shown by Colebrook that serum taken 

 from a patient with the disease will agglutinate the causal micro-organism. 

 The diagnostic value of cutaneous tests with vaccines has been appraised 

 by Conant et al. who reported that patients with actinomycosis are sensi- 

 tive to both intracutaneous and subcutaneous injections of a vaccine made 

 from the causative organism. 



(f ) Differential diagnosis.— While the absolute diagnosis rests on the 

 demonstration of the ray fungus in the pus (see pp. 320 ff. ), the clinical 

 picture is usually highly suggestive. The location, the development of 

 sinus tracts and the presence of white or yellow granules in the pus are 

 characteristics rarely noted with other infections. Sporotrichosis may be 

 differentiated by the absence of granules in the discharge, by the devel- 

 opment of successive lesions along a lymphatic chain and by breaking down 

 of the lesions into ulcerations. Sporotrichum schencki is readily cultured 

 but not demonstrated in pus. Granuloma coccidioides is characterized by 

 the development of soft granulomatous lesions on various parts of the body, 

 with symptoms of systemic infection. Coccidioides immitis is present in 

 the pus, and guinea-pigs readily become infected. Tuberculosis may be 

 simulated in lesions in the skin, in the lungs and in the vertebrae. Finding 

 the ray fungus is necessary to determine the diagnosis; cultures of sputum 

 which yield Actinomyces may be misleading, since the fungus is frequently 

 saprophytic in the mouth. The roentgen picture of the lungs usually shows 

 the disease affecting the lower lobes and rarely reveals cavity formation. 

 When the vertebral column is affected, tuberculosis is simulated, but 

 tuberculosis is usually limited to the anterior portion of the vertebral 

 bodies. With involvement of the abdominal viscera, the diagnosis will be 

 determined if actinomycosis is kept in mind as a possible cause for per- 

 sistent sinuses following operation and if wet preparations of material 

 from unusual pustular conditions found at operation are made routinely 

 and examined for the ray fungus. When the tongue alone is involved, 

 syphilis, carcinoma, tuberculosis or pyoderma may be suspected until the 

 ray fungus is demonstrated. An elevated sedimentation rate and a moder- 

 ate leukocytosis may occasionally be helpful laboratory findings. 



