Seborrheic dermatitis is a common, chronic skin condition that primarily appears in areas with increased oiliness and high activity of the sebaceous glands, causing inflammation in the affected region. It is characterized by periods of remission and flare-ups, and leads to redness and flaking of the affected skin. It affects approximately 5% of the population and is more commonly observed in men.
There is no clearly defined single cause of seborrheic dermatitis, and it is most likely a multifactorial condition.
However, several factors are known to play a significant role in its development, such as the lipophilic fungus Malassezia, which is isolated in the majority of cases on the skin of individuals with seborrheic dermatitis. Genetics, hormonal influences, environmental factors (e.g., climate), and psychological factors (e.g., stress) also contribute to the onset of the condition.
Seborrheic dermatitis primarily appears on the scalp, the face (around the nose, behind the ears, on the eyebrows), and the upper torso. Some of the characteristic features of the condition include:
- Winter flare-ups with improvement during the summer after sun exposure (a relapsing condition)
- Usually mild and manageable itching
- Coexistence of oily and dry skin on the face
- Localized or diffuse fine “dandruff-like” scaling on the scalp
- Light-colored, erythematous, thin, scaly, and poorly defined plaques in the skin folds and on both sides of the face
- Slightly red, thin plaques with indistinct borders and mild scaling in the facial folds and on the eyebrows
- Rash in the armpits, under the breasts, in the groin folds, and in the genital area, among others
In infants, the condition usually appears within the first three months of life with greasy yellow scales that adhere symmetrically to the scalp, eyebrows, and eyelids. More rarely, erythematosquamous lesions may appear on the face and in the perigenital area.
Among other conditions, seborrheic dermatitis should be clinically differentiated from atopic dermatitis, psoriasis, Langerhans cell histiocytosis, dermatophytosis, other types of dermatitis, as well as pityriasis rosea.
Individuals affected by seborrheic dermatitis should follow a consistent skincare and moisturizing routine to help keep symptoms under control. Treatment often involves one or a combination of the following options:
- Keratolytic agents to remove scales (when deemed necessary)
- Antifungal agents to reduce the load of pathogenic fungi on the skin
- Mild topical corticosteroids for 1–3 weeks to reduce inflammation during acute flare-ups
- Calcineurin inhibitors
In resistant cases in adults, oral itraconazole, antibiotics, or phototherapy may be recommended. In addition, high levels of stress and anxiety should be managed, as they contribute to the worsening of the condition.
The main difference between dandruff and seborrheic dermatitis is that the former represents a mild, non-inflammatory form of flaking, while the latter is inflammatory. Dandruff could be considered an early stage of seborrheic dermatitis, as the issue often begins with a disruption in the skin’s natural shedding process—possibly due to stress, an unbalanced diet, excessive use of styling products, or infrequent hair washing.
This imbalance leads to an increase in the population of the fungus Malassezia globosa, which feeds on the fatty acids produced by the scalp, eventually triggering localized inflammation and more intense flaking.
Another visible difference is that the flakes in seborrheic dermatitis tend to be greasy and yellowish, whereas in dandruff they are dry and whiter. Finally, dandruff is limited to the scalp, while seborrheic dermatitis can also appear on the eyebrows and around the nose.