The condition affecting your scalp and the area behind your ears is likely to be seborrhoeic dermatitis or scalp psoriasis, both common dermatological conditions with overlapping features but distinct characteristics.
Seborrhoeic dermatitis typically presents with greasy, yellowish scaling on an erythematous base involving the scalp, nasolabial folds, hairline, eyebrows, and postauricular areas. It often causes patchy, scaly, and inflamed skin in these seborrhoeic (oil-rich) regions, explaining the involvement of the scalp and behind the ears NICE CKS,Scheufele et al. 2024.
In contrast, scalp psoriasis generally presents as well-demarcated, erythematous plaques with thicker silvery-white scales on the scalp; it can also involve the extensor surfaces of the elbows and knees and nails showing pitting NICE CKS,NICE CG153,Scheufele et al. 2024. Psoriasis plaques tend to be more sharply defined and thicker than seborrhoeic dermatitis lesions, which are often greasy rather than powdery.
Distinguishing between these two can be challenging because seborrhoeic dermatitis and psoriasis may coexist and share clinical features such as scaling and erythema in scalp regions, including the area behind the ears NICE CKS,Scheufele et al. 2024. Additional features favoring psoriasis include nail pitting and thicker, more adherent silvery scaling.
Other differential diagnoses to consider include atopic dermatitis, contact dermatitis, and fungal infections; however, the distribution and typical scaly eruptions on scalp and postauricular skin most commonly suggest seborrhoeic dermatitis or psoriasis NICE CKS,Scheufele et al. 2024.
Both conditions are influenced by immune dysregulation and involve skin microbiota alterations. Recent evidence supports the role of skin microbiome imbalance (dysbiosis) contributing to inflammation in both seborrhoeic dermatitis and psoriasis, with emerging interest in topical probiotics as adjunctive therapy to modulate skin microbiota, reduce inflammation, and restore barrier function Scheufele et al. 2024,Nowicka et al. 2025.
Treatment differs: seborrhoeic dermatitis usually responds well to antifungal or mild anti-inflammatory topical agents, while scalp psoriasis often requires potent topical corticosteroids, vitamin D analogues, or combination treatments for effective control NICE CKS,NICE CG153.
In summary, the scalp and postauricular condition you describe is most consistent with seborrhoeic dermatitis or scalp psoriasis, and clinical features coupled with examination can help differentiate these or identify coexistence. Consultation with a clinician is recommended for diagnosis confirmation and tailored management.
Key References
- CKS - Fungal skin infection - body and groin
- CKS - Seborrhoeic dermatitis
- CKS - Blepharitis
- CG153 - Psoriasis: assessment and management
- (Scheufele et al., 2024): Presentations of Cutaneous Disease in Various Skin Pigmentations: Seborrheic Dermatitis.
- (Graham et al., 2024): Differential diagnosis of posterior scalp hair loss.
- (Nowicka et al., 2025): Topical Probiotics as a Novel Approach in the Treatment of Chronic Dermatoses Associated with Skin Dysbiosis: A Narrative Review.