What causes seborrheic dermatitis (seborrhoeic dermatitis) in adults?

From the Guidelines

Cradle cap in adults, known as seborrheic dermatitis, is caused by an overproduction of oil (sebum) in the skin combined with an inflammatory reaction to Malassezia yeast, which naturally lives on the skin. This condition typically appears as flaky, greasy patches on the scalp and sometimes other oily areas of the body. Contributing factors include stress, hormonal changes, certain medical conditions like Parkinson's disease or HIV, and genetic predisposition 1. According to the most recent evidence, seborrheic dermatitis is a common condition affecting the ears, scalp, central face, and other sebaceous areas of the skin, presenting with greasy yellowish scaling, itching, and secondary inflammation from Malassezia yeast 1.

The treatment usually involves medicated shampoos containing ingredients like ketoconazole 2% (Nizoral), selenium sulfide (Selsun Blue), zinc pyrithione, or salicylic acid. These should be applied to the affected area, left on for 5-10 minutes, then rinsed thoroughly, typically 2-3 times weekly until symptoms improve. For more severe cases, topical corticosteroids like hydrocortisone 1% may be needed. The condition tends to be chronic with periods of flare-ups and remissions, so maintenance therapy with medicated shampoo once weekly is often recommended after clearing 1.

Some key points to consider in the management of cradle cap in adults include:

• Avoiding triggers like stress and maintaining good scalp hygiene can help prevent recurrences
• Using topical antifungal medications to reduce the amount of yeast present and topical anti-inflammatory medications to reduce inflammation and itch
• Considering the potential for coexisting conditions like psoriasis and discoid lupus erythematosus, which have characteristic skin lesions and often involvement of other areas of the skin 1.

Overall, the management of cradle cap in adults requires a comprehensive approach that takes into account the underlying causes and contributing factors, as well as the potential for coexisting conditions. By prioritizing the use of medicated shampoos and topical corticosteroids, and maintaining good scalp hygiene, individuals with cradle cap can effectively manage their symptoms and prevent recurrences.

From the Research

Causes of Cradle Cap in Adults

• Cradle cap, also known as seborrheic dermatitis, is a superficial fungal disease of the skin, occurring in areas rich in sebaceous glands 2.
• It is thought that an association exists between Malassezia yeasts and seborrheic dermatitis, which may be due to an abnormal or inflammatory immune response to these yeasts 2.
• The exact cause of cradle cap in adults is not fully understood, but it is believed to be related to a combination of factors, including:
  • Overproduction of skin oil
  • Sensitivity to hair care products
  • Stress
  • Hormonal changes
  • Fungal infections, such as Malassezia 2, 3, 4
• Seborrheic dermatitis can be triggered by various factors, including:
  • Genetic predisposition
  • Environmental factors, such as climate and humidity
  • Immune system disorders
  • Nutritional deficiencies 3, 4

Treatment and Management

• Treatment for cradle cap in adults typically involves the use of antifungal agents, such as ketoconazole, itraconazole, and terbinafine 2, 3.
• Topical antifungals, such as ciclopirox and zinc pyrithione, have also been shown to be effective in treating seborrheic dermatitis 4, 5.
• Maintenance therapy with zinc pyrithione or selenium disulfide shampoos may help to prevent relapses and extend the lesion-free period 6.