(Seborrhagia; Steatorrhoea; Dandruff; Pityriasis simplex)
Definition. A functional disorder of the sebaceous glands, characterized by increased, decreased or altered sebum and appearing on the surface in the form of oil, crusts or scales.
It is so difficult to separate clinically those forms of seborrheic disease which are strictly non-inflammatory and those that are inflammatory in some degree, no matter how slightly, that it seems wise first to discuss the two varieties of non-inflammatory seborrhea, namely seborrhea oleosa and seborrhea sicca, as preliminary or mild forms of the inflammatory type, known as dermatitis seborrhoica, which naturally follows the milder forms.
Symptoms. There is also much confusion as to just what conditions belong under the head of seborrhea proper. Of course the oily type, seborrhea oleosa, may properly be included in this group, but the division line between the marked scaly and crusted conditions of seborrheal origin and dermatitis seborrhoica is hard to draw. Either form of seborrhea may be slight, limited and of short duration or widespread, marked and persistent. The two forms may coexist in the same person at the same time and, while the disease may appear on the body wherever there are oil glands, it is usually found on the face, scalp, upper part of the trunk and genital regions.
Seborrhea oleosa is characterized by an excessive secretion of an oily fluid and is commonly seen on the scalp and the middle third of the face. In the latter location it is more common than dry seborrhea, especially on and about the nose, the nasolabial fold and corners of the mouth. When the scalp is involved, the oil covers both the skin and the hairs and if baldness exists, the surface presents a markedly polished appearance. The secretion may solidify as in dry seborrhea but the oily condition usually remains. Frequently drops of oil can be wiped from the surface in the pronounced forms and the oil ducts are usually patulous or clogged with comedones. Fine dust may become attached to the oily matter and give the surface a dark or dirty appearance. The skin is usually cool to the touch but it may appear slightly reddened or pale. Acne often coexists with oily seborrhea and Sabouraud regards the latter as preliminary to acne and alopecia prematura. The free oily secretion in the negro is more physiological and gives to the exposed parts a constant shiny look.
Seborrhea sicca may be studied according to location. Upon the scalp (seborrhea capitis) where it is commonly found in infancy, it constitutes the milk crust (crusta lactea). This form originates from the dried vernix caseosa remaining on the vertex of the new-born, or it may arise from too thorough and too frequent cleansing. In children and adults, the disease is usually symmetrical and appears in the form of yellowish-white, greasy scales somewhat adherent to the surface and often penetrated by some of the hairs. The smaller particles (dandruff) lodge upon the shoulders of the person affected when shed from the surface. The disease may be circumscribed or occur in more or less diffused patches, and occasionally the whole scalp may be uniformly involved. But in any case, the vertex and crown of the head are affected if the disease lasts for any time. In this last instance, permanent alopecia is sure to ensue but fortunately it is symmetrical, as a rule. The loss of hair in infancy is always temporary. The surface involved is usually anemic, pale gray in color, but dark red, circular, moist patches may be found, usually due to fingernail excoriations made in an attempt to relieve slight itching. Add to this condition increased hyperemia or eczematous inflammation and you have a true seborrheoic dermatitis or, as some have chosen to call it, seborrheic eczema.
Seborrhea of the face (seborrhea faciei) may be scaly or crusted, exist independently or in conjunction with the disease on the scalp, and is usually most marked about the nose, to a less degree, on the cheeks, forehead, eyelids and chin. The sebaceous matter is slightly adherent to the surface and appears as dirty yellow to yellowish-brown scales which reform rapidly when they are removed. This simple condition often passes into one of seborrheic dermatitis. The skin affected is commonly pale or slightly reddened and shows the patulous openings of the sebaceous ducts into which formations, on the under part of the crust, are fitted.
Seborrhea of the body (seborrhea corporis), especially over the sternum and between the scapuli, appears as circumscribed, round or irregular patches covered with dry or greasy scales. These may occur singly or in groups and, owing to the friction present, may not appear as pronounced as some of the other forms. The principal lesions may have a popular appearance and form patches by peripheral extension and coalescence with central clearing, later developing circinate or gyrate formations. These seborrheic papules are common in the inflammatory form of seborrhea,later described as dermatitis seborrhoica. When the umbilical region is involved the secretion is apt to decompose, giving rise to a fetid odor and a seropurulent discharge which eventually produces an eczematous condition.
The genitalia (seborrhea genitalium) may be involved with the oily variety at the start but later the crusted form is usually seen. In men, the glans and corona of the penis and the region behind the prepuce may be the seat of decomposition of a normal oily secretion (smegma), which gives rise to reflex disturbances of various kinds, especially in the young. The same condition may arise in women where semisolid accumulations occur about the clitoris, vestibulum and labia. Females, while less liable to reflex disorders, are more subject, from the larger surface exposed, to greater decomposition of the secretion and secondary irritations even to the point of ulceration.