What are the symptoms of seborrheic dermatitis?

Seborrheic dermatitis manifests with symptoms including erythematous plaques, greasy scales, pruritus at affected sites, dryness and scaling of the skin, and localized exudation with crusting. These manifestations predominantly occur in areas with abundant sebaceous gland activity—such as the scalp, face, and upper trunk—and symptom severity varies depending on disease intensity. If extensive skin erosion or persistent fever develops, prompt medical evaluation and treatment are strongly recommended.

1. Erythematous Plaques:

In affected areas, well-demarcated, light-red plaques appear; their color may deepen with more severe inflammation. The underlying erythematous base is often associated with increased sebum production. Friction or irritation can gradually expand the plaque’s borders and exacerbate other associated discomforts.

2. Greasy Scales:

Yellowish, greasy scales adhere to the surface of erythematous plaques and tend to stick tightly to the skin; they recur readily after removal. On the scalp, these scales cling to hair shafts and shed as abundant dandruff, accompanied by a pronounced oily sensation.

3. Pruritus at Affected Sites:

Pruritus of varying intensity occurs at lesional sites. It typically intensifies under conditions such as emotional stress, hot or humid environments, or consumption of fatty foods. Repeated scratching damages the epidermis, potentially leading to excoriations and secondary infection.

4. Dryness and Scaling:

In some individuals, lesions exhibit relatively low sebum production and instead present with dry, white scales—commonly observed on the face and extremities. The skin may feel tight and is often misdiagnosed as simple xerosis; even intensive moisturizing care frequently fails to fully resolve the scaling.

5. Localized Exudation and Crusting:

With severe inflammation, serous exudate appears on the skin surface; upon drying, it forms yellowish crusts. Underlying these crusts lies an eroded wound surface. Forced removal of crusts may cause bleeding and accelerate inflammatory spread, thereby prolonging recovery time.

Reduce intake of sweets and fried foods, maintain regular sleep-wake cycles, and avoid staying up late. Use gentle cleansers and avoid over-cleansing to preserve the skin barrier and lower the risk of recurrent seborrheic dermatitis.