Give the cause or causes of seborrhœa.
General debility, anæmia, chlorosis, dyspepsia, and similar conditions are to be variously looked upon as predisposing.
In some instances, however, the disease seems to be purely local in character, and to be entirely independent of any constitutional or predisposing condition. The view recently advanced that the disease is of parasitic nature and contagious has been steadily gaining ground.
What is the pathology of seborrhœa?
Seborrhœa is a disease of the sebaceous glands, and probably often involving the sweat-glands also; its products, as found upon the skin, consisting of the sebaceous secretion, epithelial cells from the glands and ducts, and more or less extraneous matter. Not infrequently evidences of superficial inflammatory action are also to be found, and it is especially for this type that the name eczema seborrhoicum is most appropriate. In long-continued and neglected cases slight atrophy of the gland-structures may occur.
With what diseases are you likely to confound seborrhœa?
Upon the scalp, with eczema and psoriasis; upon the face, with lupus erythematosus and eczema; and upon the trunk, with psoriasis and ringworm.
As a rule, the clinical features of seborrhœa are sufficiently characteristic to prevent error.
What are the differential points?
Eczema, psoriasis, and lupus erythematosus are diseases in which there are distinct inflammatory symptoms, such as thickening and infiltration and redness; moreover, psoriasis, and this holds true as to ringworm also, occurs in sharply-defined, circumscribed patches, and lupus erythematosus has a peculiar violaceous tint and an elevated and marginate border. A microscopic examination of the epidermic scrapings would be of crucial value in differentiating from ringworm.