the symptoms of seborrh[oe]a of the trunk and other parts.#

[Illustration: Fig. 7.
A normal sebaceous gland in connection with a lanugo hair.
(_After Neumann._)
_a_, Capsule; _b_, fatty secretion; _c_, _h_, secreting cells; _d_, root
of lanugo hair; _e_, hair-sac; _f_, hair-shaft; _g_, acini of sebaceous
gland.]

Seborrh[oe]a corporis differs in a measure, in its symptoms, from
seborrh[oe]a of the scalp and is usually illustrative of the variety
known as eczema seborrhoicum; it occurs as one or several irregular or
circinate, slightly hyperaemic or moderately inflammatory patches,
covered with dirty or grayish-looking greasy scales or crusts, usually
moderate in quantity, and upon removal are found to have projections
into the sebaceous ducts. It is commonly seen upon the sternal and
interscapular regions. It rarely exists independently in these regions,
being usually associated with and following the disease on the scalp. It
may also invade the axillae, genitocrural, and other regions.

#What is the usual course of seborrh[oe]a?#

Essentially chronic, the disease varying in intensity from time to time.
In occasional instances it disappears spontaneously.

#Give the cause or causes of seborrh[oe]a.#

General debility, anaemia, 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 seborrh[oe]a?#

Seborrh[oe]a 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 seborrh[oe]a?#

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 se