Seborrheic dermatitis is a chronic skin condition that affects millions of people worldwide. Its estimated UK prevalence is 3-5%. Its characteristics include red, inflamed skin, often covered with flaky, white or yellowish scales. The condition most commonly affects areas of the body rich in sebaceous (oil) glands, such as the scalp, face, and chest. Despite the fact that so many people suffer from it, seborrheic dermatitis is one of those skin conditions that is misunderstood, with misdiagnosis or delayed treatment being related hazards. Understanding this condition from a doctor’s point of view begins with recognising its hallmark features and knowing that it is a medical condition that can impact daily life. If you suffer from this condition, you will already be aware.