Seborrheic dermatitis, also known as cradle cap or dandruff, is a common form of eczema that affects the scalp in infants, children, and adults. Seborrheic dermatitis is a chronic, relapsing, and remitting disease that is usually easily treatable, however, more difficult to treat cases can be frustrating for patients.
Cause
Despite the name, seborrheic dermatitis has not been proven to be a disorder of sebaceous gland dysfunction. However, we do know that there is some involvement due to the distribution of the disease in highly sebaceous gland dependent areas. The sebaceous glands may play a role in providing a favorable environment for the growth of the fungi Malassezia. Malassezia is a part of the normal skin flora but can overgrow in seborrheic dermatitis.
Presentation
Seborrheic dermatitis can present as mild scaling to a base of well-demarcated, erythematous plaques with overlying greasy, yellowish scale. Commonly affected areas include the scalp, external ear, face, chest, axilla, and groin. It can worsen with increased stress or in in drier, colder months, with improvement in the summer.
Diagnosis
Seborrheic dermatitis is generally diagnosed clinically based on the appearance, location of lesions, and patient symptoms.
Differential Diagnosis
The differential includes squamous cell carcinoma, benign lichenoid keratoses, verruca, inflamed seborrheic keratosis, porokeratosis, and forms of eczema (psoriasis, seborrheic dermatitis).
Treatment
OTC anti-dandruff shampoos (zinc pyrithione 1% and selenium sulfide 2.5%) are typically a patient’s initial treatment for seborrheic dermatitis. If these are not successful, a patient will typically present to the clinic. Topical antifungal agents (ketoconazole or ciclopirox) are first line for treatment of mild seborrheic dermatitis. The addition of a topical calcineurin inhibitor or topical corticosteroid may be necessary in more severe cases or in difficult to treat cases. Topical anti-fungals help reduce the burden of Malassezia and are anti-inflammatory. Topical corticosteroids and calcineurin inhibitors offer anti-inflammatory benefits. The key to treatment of seborrheic dermatitis is ensuring the medicated shampoos are allowed to sit on the scalp for 5-10 minutes before rinsing.
Prevention
Seborrheic dermatitis is a relapsing and remitting disease, therefore, continued use of treatments will be necessary to keep the disease at bay. Once under control, patients are usually able to cut back on frequency of use of their topical medications.
Written by Sydnee Eck, PA