Seborrheic dermatitis is generally areas of erythema covered by inflamed yellow oily scales. It is often found around the front hairline and forehead but can also affect any part of the scalp, neck, face, back and other areas of the body. It is normally an itchy condition.
The yeast, Malassezia Globosa, is abundant on the skin with this problem and may play a causative role by acting on the sebum to produce free fatty acids. It is the free fatty acids that irritates the skin which then leads to the inflammatory process and the scaling.
It can affect females at almost any age but generally found in men aged 16 to 40 and is known as cradle cap in babies.
Hormonal factors can play a part as the sex hormones and thyroxine influence the sebum production. Although active at birth the production of sebum subsides soon after adolescence when the increase in androgen production increases the size of the sebaceous glands which, in turn, increases sebum production.
Females and males of 13 to16 produce about the same amount of sebum. However, after age 16, sebum is much greater in males due to the influence of the increase in androgens from the testes.
In females it is the combined production of androgens from the adrenal cortex and ovaries that influences sebum. In females, excessive oiliness could indicate a hormonal imbalance or the influence of certain oral contraceptives on the skin.