Difference I: They have different root causes
Whilst scalp psoriasis and dandruff are both caused by a high skin turnover rate, they have different underlying causes. In both conditions, the replacement process by which dead skin cells are shed to make room for new cells is sped up, and so they clump together to form big clusters. However, whilst the scales produced by psoriasis are reminiscent of dandruff flakes, that is the only similarity between them.
Scalp psoriasis is first and foremost a genetic condition that is deeply rooted in the immune system. Sometimes it is inherited from your parents – one naughty little gene can start the trouble – and at other times it can appear out of nowhere. If you have existing psoriasis on other body parts, you are even predisposed to having an outbreak of scalp psoriasis if you hurt your head.
This process is known as the Koebner phenomenon, and it describes how psoriasis can spread to an area of skin injury – for example, if your cat scratches your forehead, if your head gets sunburnt on the beach or if you knock it on the doorframe.
However, the shedding of dead skin cells that is at the heart of dandruff is reported to have altogether different causes. Some dermatologists point their fingers at a little fungus called Malassezia. Everybody has minute amounts of this yeast, particularly in greasy areas where skin oils build up (on the scalp and the upper torso), but for some individuals it develops into dandruff.
This yeast feeds off the skin oils and secretes oleic acid, which triggers the scalp to bump up its production of skin cells, which leads to dandruff. Other reasons that have been listed include hormonal imbalances (as it normally starts after puberty, when hormones are going haywire), irregular hair brushing, infrequent shampooing, dry skin and stress.
Difference II: They look different
The second major difference between the two conditions is their appearance and the locations where they surface. You don’t need to have a trained eye to see the dissimilarity!
Firstly, whilst dandruff normally appears where the hair grows, scalp psoriasis has no bounds. It can extend beyond the hairline and into the forehead, as well as onto the back of the neck and around the ears.
Secondly, the actually flakes are different. The scales that are produced by scalp psoriasis are generally small and may even look powdery with a silvery sheen. However, dandruff flakes are usually bigger and more “built up”, like a section of roof tiling. There might be a degree of overlapping, particularly in cases of severe scalp psoriasis when the scales are thicker and form “crusts”, but usually this key visual difference between the two is present.
Thirdly, scalp psoriasis is characterized by inflammation and redness, whereas dandruff is not. Sometimes the itchiness that dandruff causes makes some people scratch their heads until their scalps glow red, but its not the same as the inherent red patches with psoriasis.
Difference III: They (might) need different treatment
Since the symptoms are alike, the first line of treatments for scalp psoriasis and dandruff are sometimes similar. However, if the cases are particularly stubborn, they require different approaches. Psoriasis in particular may be resistant to regular treatments due to its genetic nature.
Both scalp conditions normally respond well to certain medicated shampoos which contain coal tar and salicylic acid. This type of acid is great for de-scaling and smoothing over patches of skin. They are also normally available over-the-counter.
For severe dandruff, you might be prescribed an anti-yeast shampoo containing either selenium sulphide, or ketoconazole. Both of them are natural born killers when it comes to the tiny fungus living on your head.
However, anti-yeast shampoos will do nothing for your psoriasis (unless you have an existing yeast condition that is exacerbating your psoriasis!). For severe cases of scalp psoriasis, you might be prescribed a topical steroidal ointment or a few sessions of phototherapy with ultraviolet (UV) light.
Having either scalp psoriasis or dandruff can be very embarrassing, especially when you’re wearing dark clothing and the flakes stand out like little stars at night. However, it’s not the end of the world. By diagnosing your condition properly, you can determine which products to use and which approach works best. Don’t forget to browse our site for psoriasis treatment ideas.