Seborrheic dermatitis is a common, chronic, inflammatory skin condition that primarily affects areas of the scalp, face, and trunk. It is characterized by erythematous, scaly, and sometimes pruritic lesions that are often accompanied by a variable degree of erythema and scaling. The exact cause of seborrheic dermatitis is not fully understood, but it is thought to be a combination of genetic, hormonal, and environmental factors.
The scalp is the most common site of involvement in seborrheic dermatitis. It presents as erythematous, scaly plaques with variable amounts of erythema and scaling. The hairline, the eyebrows, the sides of the nose, and the ears are other common sites of involvement. The face is another common site of involvement, particularly the nasolabial folds and the peri-oral region. The chest and the back are also often affected.
The clinical presentation of seborrheic dermatitis can vary depending on the severity of the disease and the specific body site affected. Mild cases may present with minimal scaling and erythema, while more severe cases may be associated with significant erythema, scaling, and pruritus. The lesions may be annular or polycyclic and may be associated with a greasy or waxy scale.
The differential diagnosis for seborrheic dermatitis includes other common inflammatory skin conditions such as psoriasis, eczema, and tinea. The diagnosis is usually made on the basis of the clinical presentation and the distribution of the lesions. A skin scraping or a fungal culture may be performed to rule out tinea. A biopsy may be necessary in some cases to confirm the diagnosis and to rule out other conditions.
The mainstay of treatment for seborrheic dermatitis is the use of topical anti-inflammatory agents such as corticosteroids, calcineurin inhibitors, and salicylic acid. Topical corticosteroids are the most commonly used agents for the treatment of seborrheic dermatitis. They are effective in reducing inflammation and scaling. Calcineurin inhibitors such as tacrolimus and pimecrolimus are also effective in the treatment of seborrheic dermatitis, particularly in areas of the face and scalp that are difficult to treat with topical corticosteroids. Topical salicylic acid can be used to soften and remove scale.
Shampoo containing coal tar, selenium sulfide, salicylic acid, or pyrithione zinc can be used to treat scalp involvement. Light therapy, such as UVB or narrow-band UVB, can be used to treat more severe cases of scalp involvement. Systemic therapy with oral antifungals or oral antibiotics may be considered in patients with severe or recalcitrant disease.
In most cases, seborrheic dermatitis is a chronic condition that requires ongoing management. Patients should be educated about the importance of maintaining a regular skin care routine and using appropriate topical medications as prescribed. They should also be counseled about triggers such as stress, which can exacerbate the condition.