How to distinguish psoriasis from seborrheic dermatitis?
Seborrheic dermatitis is a chronic inflammatory dermatosis mainly affecting adults (and infants in the form of "cradle cap") on the face, scalp, ears, and sometimes on the torso, genitals or in the skin folds (hence the potential confusion with inverse psoriasis). Yeasts of the Malassezia genus present on the skin’s surface undoubtedly play a major role in the physiopathology of seborrheic dermatitis, which is why antifungal creams and shampoos are often effective in the treatment of seborrheic dermatitis but have no effect on psoriasis.
So, how do you tell the difference between psoriasis and seborrheic dermatitis?The main difference is the lesions' appearance:
- Seborrheic dermatitis plaques are covered with yellower and oilier scales than psoriasis-type plaques;
- Itching is less common in seborrheic dermatitis than psoriasis, although it can be severe in some patients. When patients have psoriasis on their body and seborrheic dermatitis on their face, it is referred to as sebo-psoriasis.