Scalp matters: Understanding dandruff and scalp eczema
This is a post that I wrote for BGLH but it is quite relevant for those of you suffering from scalp issues so here goes!
Quite often people mix up dandruff and scalp eczema. The truth is both of these conditions are very similar and they both actually share the same cause but knowing the difference between the two can greatly help to get the correct treatment and management.
What is dandruff?
Dandruff is characterised by loose skin flakes which are normally white in colour. There is also usually some itching but this is usually not very severe.
What is eczema?
Scalp eczema,like dandruff is also characterised by flaking and itching. The big difference is that scalp eczema often results in greasy, yellowish flakes and the itching can be quite severe and accompanied with inflammation (meaning skin feels hot and is swollen). Additionally if you have eczema elsewhere (under the nose, on the hands/legs etc) the likelihood is that what you may perceive as dandruff on your head may actually be eczema.
What causes dandruff and seborrheic dermatitis?
Dandruff and eczema have a similar cause and three main things create the right environment:
1. Fungus: Our skin and infact our bodies are covered in bacteria and fungi both inside and out. This is perfectly normal and should not be any cause for alarm. The reason why the scalp begins to flake is that a normal fungus that is found on the skin is produced in higher amounts than normal. This fungus is known as Malassezia and it affects the scalp because its food source is a specific fat found in sebum.
2. Sebum: The fungus Malassezia uniquely prefers one specific fat in sebum known as oleic acid. By specifically choosing to consume this fat above all others in sebum, the composition of sebum is altered . This alteration is then thought to lead to the cells on the scalp losing their adhesiveness and flaking off.
3. Individual susceptibility. The fact is that some people have dandruff and some do not. Some people have eczema and others do not. For some people high levels of the fungus -Malassezia or indeed of its food source - oleic acid, does not result in dandruff. However, for others, even slight changes in the balance leads to problems.
Dandruff and scalp eczema are not linked to washing hair frequently or infrequently. Having dandruff or scalp eczema does not mean that your personal hygiene is low.
1. J Investig Dermatol Symp Proc pp 15–19, (2007)
2. J Investig Dermatol Symp Proc 10:194–7 (2005)
3. Science 304:304–7 (2004)