Often, people can confuse these two terms. There is a difference though, however. Knowing the difference between the two can greatly help you to correct and treat the issue.
What is dandruff?
Dandruff can be characterised by loose flakes of skin which are normally white in colour. Itching can also be sometimes involved, but not as severe. Dandruff is not caused by dryness, but rather too much oil (sebum).
What is eczema?
Eczema is also known medically as seborrheic dermatitis, and often results in inflammation and red flaky patches of the skin. Like dandruff, it is also characterised by flaking and itching. The big difference is that scalp eczema is accompanied by inflammation and often results in greasy, yellowish flakes. Additionally, if your eczema also shows up on other parts of the bodies (usually on joints – such as the fingers, wrist, knees, elbows), the likelihood is that what you may perceive as dandruff on the scalp may actually be eczema.
What causes dandruff and seborrheic dermatitis/eczema?
3 main things can contribute to dandruff and eczema, which causes the flaking and itching to happen:
Our skin and internal bodies are covered in bacteria and fungi. A healthy person has 80% good bacteria and 20% bad bacteria; the scalp will begin to flake when a normal fungus found on the skin is produced in greater amounts than normal. This fungus is known as Malassezia, and it feeds on a specific fat that is found in sebum. Normal skin on your scalp renews every 24 days by forming new skin cells underneath, while the old cells slough off.
Malassezia lives on the scalps of most healthy adults without causing problems. But sometimes it grows out of control and feeds on the oils in your hair follicles, which causes irritation that leads to increased cell turnover. This results in a large number of dead skin cells that fall off and clump together with oil from your hair, making them appear white, flaky and visible.
The fungus Malassezia specifically feeds on a fat in sebum, known as oleic acid. Since it consumes more of this fat above all others, it alters the composition of sebum in the scalp. This alteration affects the other cells on the scalp, which begin to lose its adhesiveness and flake off.
3. Individual susceptibility:
Some people are more susceptible to dandruff than others. For example, some people are more prone to having dandruff or eczema (due to diet or other factors), while others are not affected by it, even when they have high levels of the fungus, Malassezia, or its food source. For others, even slight changes in the balance leads to problems.
For more information, you can read more on the causes of eczema, tips to treat scalp eczema, or shampoo recommendations for scalp eczema.