MALASSEZIA 361 



many lesions producing acne (comedones or blackheads). Sabouraud (1932) 

 recognizes pityriasis simplex capitis (dandruff), pityriasis steatoid (seborrheic 

 eczema of Unna) usually a later stage of dandruff, which eventually leads to 

 seborrheic alopecia (baldness), acne vulgaris (comedones or blackheads), 

 papular seborrheas, in connection with acne rosacea and, finally, seborrheic 

 warts of old age. Acton and Panja, using a dry, fatty medium, show that all 

 conditions are due to the same organism, although secondary infections may 

 occur. Two other kinds of scaling are common, pityriasis versicolor caused 

 by Malassezia furfur, and pityriasis flava (tinea flava of Castellani) caused by 

 Malassezia tropica. 



Probably pityriasis capitis is the most important, as the scalp forms a con- 

 tinual source of scales for the transfer to other portions of the body, and until 

 baldness begins to appear in middle life, it is easily overlooked and seldom 

 treated by a physician. Also these scales usually contain Staphylococcus alhus 

 or S. aureus, thus forming a reser\^oir for these organisms to spread to other 

 parts of the body, producing pimples, boils, etc. 



When Malassezia grows on delicate skin, as that of the face, flexure of joints, 

 etc., of children, the desquamation leaves the basal cell layer exposed, allow- 

 ing the invasion of the corium by streptococci with the production of seborrheic 

 eczema and eczema rubrum of children. 



The synonymy may be tabulated as follows : 



General terms: seborrheic dermatitis, seborrhagia, steatidrosis, seborrhea of Hebra, 

 hyperidrosis oleosa of Unna, flux sebacea of Eayer. 



Scalp lesions: dandruff, pityriasis capitis, seborrheic dermatitis of the scalp, seborrhea- 

 sicca, seborrhea oleosa, seborrheic alopecia. 



Glabrous skin: seborrheic dermatitis, pityriasis circinata, pityriasis steatoides, flannel 

 rash, seborrhea corporis, lichen circinatus. 



Acne: comedo, blackhead, grouped comedo, acne vulgaris, acne disseminata, acne 

 necrotica. 



Lips: exfoliative cheilitis. 



With streptococcus as secondary invader: seborrheic eczema and eczema rubra. 



For the benefit of the botanist who is unfamiliar with the structure and 

 development of the sebaceous glands, I give the following summary from the 

 work of Acton and Panja (1927) and of Sabouraud (1932). The embryonic skin 

 consists of two layers: a basal layer of columnar cells and Rauber's layer, 

 consisting of swollen cells which stain badly, and form a fatty substance which 

 waterproofs the fetus against the maceration of the skin by the liquor amnii. 

 About the fingers and toes, these cells are swollen, hemispheric, polyhedral, 

 and are called "the bladder cells of Zander." After birth, the superficial layer 

 begins keratinization. In the early stages of keratinization (first three years), 

 Malassezia usually infects the scalp. The sebaceous glands, which are scat- 

 tered over the surface of the body in fishes and amphibia, become associated 

 with the hair follicles in the mammals. Some of the glands which are not 

 associated with the follicles have taken on specialized functions. Of those 

 associated with the hair follicle, those in the scalp, beard, etc., are simple or 



