Synonyms. Seborrheic eczema, dermatitis seborrheica.
Seborrheic
dermatitis is an inflammatory disease of the skin that usually begins on the scalp from which it spreads
to the face, neck, and body. The disease is
characterized by dry, moist, or greasy scales, and by crusted, pinkish-yellow
or yellowish patches of various shapes and sizes; by remissions and
exacerbations, and by more or less itching. The sites of predilection
are areas in which sebaceous and sweat glands are present in large numbers. Parts commonly affected are the scalp,
supraorbital region, lids, nasolabial crease, lips, ears, sternal area,
axillae, submammary folds, umbilicus, groins and gluteal crease. The disease
usually runs a chronic course.
For the
sake of clarity the different expressions of seborrheic dermatitis will be considered topographically.
On the scalp the least severe phase—pityriasis sicca—manifests
itself as a dry flaky branny desquamation, beginning in small patches and
rapidly involving the entire surface, with a profuse amount of fine powdery
scales. An oily type of
dandruff, pityriasis steatoides, at times accompanied by erythema and an
accumulation of thick crusts, is also encountered. There is a tendency for the hair in the affected areas
to fall out, characteristically beginning on the vertex and frontal
regions and progressively receding. It is
commonly associated with premature baldness in men. Other types of seborrheic
dermatitis on the scalp are more severe and are manifested by greasy, scaling configurate patches or
psoriasiform eruptions, exudation, and thick
crusting. The disease frequently spreads beyond the hairy scalp to the forehead,
ears, postauricular regions and neck. On these areas, the patches have convex
borders and a reddish-yellow or yellowish color that is quite characteristic.
In extreme cases the entire scalp is covered by a greasy, dirty crust which has an offensive odor. In
infancy, yellow or brown scaling lesions on the scalp and accumulated
epithelial debris is called cradle cap.
On the supraorbital regions, dandruff is seen in the eyebrows,
and the underlying skin is
erythematous and pruritic, or may show definite yellowish scaling patches. The
edges of the lids may be erythematous and granular (marginal
blepharitis). The conjunctivae are injected. The lids may be
involved by yellowish-pink, finely scaly patches, the borders of which are
usually indistinct. More or less pruritus may be present. If the glabella is
involved, there may be cracks in the skin in the wrinkles at the inner end of
the eyebrow. In the nasolabial creases and on the alae nasi, there is a yellowish or reddish-yellow scaling,
sometimes with fissures. In men, folliculitis of the upper lip may
occur. There is characteristic scaling
in the aural canals and when
the disease is more advanced, there are scaly pruritic patches around the auditory
meatus and in the postauricular region, or under the lobe. In these areas
the skin often becomes red, fissured and
swollen. Serous exudation, puffiness of the ears and surrounding parts,
and regional adenopathy occur less frequently. In other cases a papular type of
eruption is present on the cheeks, nose and forehead, the papules being
scaly, greasy, yellowish or yellow-red in color, and 1 to 3 mm. in diameter.
The lips
and mucosae are not usually involved but sometimes the changes on the lips
are pronounced, resulting in cheilitis exfoliativa. The vermilion
surfaces are persistently dry, red, scaly, exfoliative and fissured.
In the axillae,
the eruption begins in the folds of skin at the apex and later progresses
to neighboring skin. The involvement may vary from simple yellowish erythema
and scaling, to more pronounced petaloid or discoid patches with fissures.
Seborrheic dermatitis is
common in the groins and gluteal crease whert its appearance may
simulate ringworm. The patches, however, are more finely scaly with less
definite borders, and are more likely to be bilateral and symmetrical and of
the typical color. In these locations, fissures occur and there may be psoriasiform patches with thick scales in the
more severe cases.
On the
upper and lower extremities the patches are more eczematoid, often lacking the characteristic color and
fineness of scale. Vesicular exudative and crusted patches are not
uncommon. The palms and soles may show a pompholyx-like vesicular
eruption or may be diffusely thickened and
scaly. Even the nails may be involved, showing longitudinal and transverse
ridges, brittleness and grayish discoloration.
The lesions may be widely distributed or generalized, with erythema, scaling, oozing, and more or less
pruritus. Often for months or years the eruption remains localized to one area,
such as the scalp, ears, sternal region or umbilicus. Less frequently subacute
or acute types are seen. In the acute stages the inflammation may be intense
with profuse swelling of the eyelids and face, moist exudation from the scalp
and ears, and papulovesicles on the palms
and soles. Secondary infections causing fur-unculosis frequently ensue.
On the extremities the cubital and popliteal regions often become lichenified
from scratching and the friction of clothing.
Generalized eruptions may be accompanied by adenopathy and may simulate
mycosis fungoides and leukemic erythroderma.
