Scleroderma, clearing up the confusion

Being a specialist in ‘Scleroderma’, I am all too aware of the confusing terminology thrown around by doctors and patients alike. If you or one of your friends or family members has one of these conditions, you probably know what I mean. I’m not 100% sure how or why it all became such a muddle, as it doesn’t have to be as confusing as it is. I am hoping this article will help clear up some of this confusion!

“Sclero” means ‘hard, hardened or hardening’ and “derma” means ‘skin’… “Scleroderma” therefore literally means hard skin. Scleroderma is an umbrella term for a group of conditions which share the feature of this skin tightness and thickening. These skin changes are due to an overproduction of collagen by skin cells called fibroblasts. The end result is loss of the skin’s natural elasticity and mobility. It instead becomes very hard, thick, tight and shiny.

The main conditions which fall into this group are systemic sclerosis (sometimes called ‘systemic scleroderma’ or just ‘scleroderma’), morphoea (sometimes called ‘localised scleroderma) and pseudoscleroderma (where the skin thickening is not caused by increased collagen).

So now that we’ve cleared that much up, how do we tell the difference between these conditions? Well, if we get the initial terminology right, after that it’s usually not all that difficult. The main difference is that morphoea ONLY involves the skin or tissues which lie directly under it (such as the fat or bones), whereas systemic sclerosis causes sclerosis (thickening and hardening) of internal organs as well; such as the lungs, heart or gastrointestinal tract. Let’s briefly talk about how we recognise and diagnose Systemic Sclerosis (SSc for short) first.

There are specific criteria which have to be met before a diagnosis of SSc can be made. These include things such as the presence of:

  • thickening and tightening of the skin on the fingers, called sclerodatyly = ‘hard fingers’
  • certain specific antibodies in the blood which are not found in other conditions, such as anticentromere antibodies or anti-Scl70 antibodies
  • abnormalities of the tiny blood vessels at the base of the nails or on the face
  • fibrotic or vascular changes in the lungs which can be detected by breathing tests or lung scans.

Importantly these features are NOT present in the other ‘Scleroderma’ conditions, and can be fairly easily seen or tested for by your Dermatologist or Rheumatologist. There are different types of systemic sclerosis, but we will talk about these another time!

Now onto morphoea… it is sometimes referred to as ‘Localised Scleroderma’. The ‘localised’ part of the name tells us that the condition is LOCALISED to the skin or the tissues just underneath (like the fat or bones). Unlike systemic sclerosis, morphoea does NOT involve the internal organs (like the blood vessels or lungs). This means that there is NO hardening or thickening of the internal organs. But! Morphoea can cause some other symptoms due to general inflammation elsewhere in body. These symptoms can include joint or muscle aches and pains, general fatigue or heartburn. We will talk more about the specifics of morphoea another time… but perhaps one of the most important things to know for now is that morphoea NEVER turns into systemic sclerosis.

And finally, what about the group of conditions called Pseudoscleroderma?

‘Pseudo’ (pronounced sue-dough) means ‘being apparently, rather than actually’ or ‘sham’. That’s right, pseudosclerodermas are only APPARENTLY scleroderma, but not ACTUALLY scleroderma! What we mean by this is that pseudosclerodermas just mimic scleroderma. Why? Because although these conditions cause the skin to feel and look hard and tight like in real scleroderma (systemic sclerosis and morphoea), the cause of the skin changes is completely different. In scleroderma, the skin is tight and thick due to over production of collagen by skin fibroblast cells. But in pseudosclerodermas, it is something else. Lots of individual conditions fall into the pseudoscleroderma group. Most are very rare like scleromyxoedema, graft versus host disease (after a bone marrow transplant) or a particular type of kidney disease. Perhaps the most common pseudoscleroderma is when the skin of the lower legs become tight due to severe varicose veins. But the key point is that pseudosclerodermas are not due to collagen overproduction; but systemic sclerosis and morphoea (localised scleroderma), are.

I hope this helps clear up some of the basics of the confusing Scleroderma terminology. We will talk more about each of these conditions in future info sheets.

If you wish to read more information now, I have written the Dermnet NZ pages on both Morphoea  and Systemic Sclerosis and you might find these answer lots of your further questions.

Written by A/Prof Amanda Saracino