Other Eczematous Eruptions

The major forms of dermatitis include atopic (see Chapter 10), contact (see Chapter 12), seborrheic, asteatotic (xerotic), stasis, and nummular. Dermatitis of special sites – i.e. hands, feet, lips, diaper area, and major body folds – is reviewed in Chapter 13, and pityriasis alba is reviewed in Chapters 10 and 54.

Seborrheic Dermatitis

• Common disorder with both an infantile and an adult form (Figs. 11.1 and 11.2); unusual in children.

Fig. 11.1 Infantile seborrheic dermatitis. Glistening red plaques of the neck, axillary and inguinal folds as well as the penis and umbilicus. Note disseminated lesions on the trunk and extremities. Courtesy, Robert Hartman, MD.

Fig. 11.2 Adult seborrheic dermatitis of the scalp, ear, and face. A Fairly sharply demarcated pink plaque with white and greasy scale. Note the fissure in the retroauricular fold. B Thin pink-orange plaques with yellow, greasy scale, especially of the melolabial fold and eyebrows. C Symmetric red-brown to violet plaques of the central forehead, nasal bridge, and medial cheeks with an associated hypopigmented figurate rim. A, Courtesy, Norbert Reider, MD, and Peter O Fritsch, MD; C, Courtesy, Jeffrey Callen, MD.

• Severe or recalcitrant seborrheic dermatitis can be a sign of underlying HIV infection or neurologic disorder.

• In adults, tends to be a chronic relapsing disorder; stress or tapering of systemic CS can lead to a flare.

• Symmetric distribution pattern that includes sites of greater sebum production – scalp, ears (external canal, retroauricular fold), medial eyebrows, upper eyelids, nasolabial folds, central chest – and major body folds.

• Lesions are pink-yellow to red-brown in color, depending on the underlying skin phototype, and they often have greasy scale, especially in the head and neck region; occasionally annular in configuration.

• On the scalp, involvement tends to be more diffuse, with well-circumscribed plaques with thicker silvery scale more characteristic of psoriasis.

• In some patients, the lesions of the scalp, ears, and major body folds have features of both seborrheic dermatitis and psoriasis, leading to the term ‘sebopsoriasis’.

• DDx: psoriasis, contact dermatitis, other causes of diaper dermatitis (see Fig. 13.4), intertrigo (see Fig. 13.2) or blepharitis, tinea versicolor (presternal), tinea capitis (especially in children), atopic dermatitis, pityriasis amiantacea and dermatomyositis (scalp); may coexist with rosacea.