Seborrheic Dermatitis Initial Assessment

The diagnosis of seborrheic dermatitis is based on clinical presentation.

Signs and Symptoms

Seborrheic dermatitis has a characteristic pattern based on age group.

Infants

Cradle cap is a diffuse or focal scaling and crusting on the vertex of the scalp sometimes accompanied by inflammation. This greasy, scaly, erythematous papular dermatitis may also involve the face, neck, retroauricular areas, axillae, and most of the body. Flexural folds may be involved, often with a cheesy exudate that manifests as diaper dermatitis that may become generalized. Post-inflammatory pigmentary changes are common. Oozing, weeping, and pruritus are typically absent. Secondary infection can also occur. Consider Leiner’s disease if lesions become widespread and erythrodermic.

Young Children

Tinea amiantacea is one or several patches of dense, plate-like scales, 2-10 cm in size, that appear anywhere on the scalp. Persistent lesions can cause temporary hair loss or produce large, oval, yellow-white plates of scales that are firmly adherent to the scalp and hair.

Adolescents and Adults (Classic Seborrheic Dermatitis) 







Dandruff is a fine, dry, white, non-inflammatory scalp scaling with minor itching. This is the mild form of scalp seborrheic dermatitis, that is also known as pityriasis sicca. Scalp changes may vary from diffuse, brawny scaling to focal areas of thick, oily, yellow crusts with underlying erythema. Severe scalp SD, also known as pityriasis steatoides, manifests as erythema and patchy, orange- to salmon-colored or grayish plaques covered with yellowish, greasy scales at the frontal hairline, medial aspects of the eyebrows, and in the nasolabial and retroauricular folds. Marginal blepharitis and external auditory canal involvement may be noted. This may also appear in the axillae, inguinal region, gluteal cleft, and umbilicus. On the extremities, seborrheic plaques may be more eczematous, less erythematous, and demarcated. 

Examine the lesion and its distribution, as seborrheic dermatitis typically affects areas rich in sebaceous glands such as the scalp and face.

Disease Severity

The severity of facial seborrheic dermatitis can be assessed using the SEborrheic Dermatitis Area and Severity Index (SEDASI), which is a scoring system that divides the face into four regions (representing 25% each) to evaluate the extent, presentation pattern, erythema, and scaling degree of the disease.