Overview of systemic sclerosis
Systemic sclerosis is an uncommon inflammatory connective tissue disease characterised by excessive collagen deposition and fibrosis of the skin (ie scleroderma1), organs and other tissues. It is also associated with vascular abnormalities (eg Raynaud phenomenon). Clinical features of systemic sclerosis by organ system or body region are listed in Clinical features of systemic sclerosis.
Two main disease variants of systemic sclerosis exist, defined by the extent of skin involvement:
- limited systemic sclerosis
- diffuse systemic sclerosis.
A localised form of disease, morphoea (also known as localised scleroderma), is more common in children than in adults. Morphoea is typically limited to the skin without systemic or organ involvement; however, in approximately one-quarter of children it is associated with extracutaneous features (eg uveitis, arthritis)Zulian, 2005. Systemic sclerosis and morphoea are quite different conditions and carry different prognoses, but are often confused; see Morphoea (localised scleroderma) for more detailed information.
Systemic sclerosis affects approximately 1 in 10 000 people globallyDenton, 2017, with a female preponderance. It occurs most frequently between the ages of 30 to 50 years but is also seen in children (rarely) and the elderly.
The prognosis for patients with systemic sclerosis depends on their age, gender, disease variant and the severity of systemic involvement. Males have a poorer outcome. The average survival from the first symptom is 30 to 40 years for limited systemic sclerosis, and 15 to 20 years for diffuse systemic sclerosis. Cardiopulmonary involvement (eg pulmonary arterial hypertension, interstitial lung disease) is the leading cause of death.
A number of common drugs should be avoided in people with systemic sclerosis; see Commonly prescribed drugs to avoid in patients with systemic sclerosis for some important prescribing considerations.
A number of commonly prescribed drugs should be avoided in people with systemic sclerosis, including:
- systemic corticosteroids—avoid prednisolone (or prednisone) if possible or, if corticosteroid therapy is necessary, avoid doses of more than 10 mg daily because there is a risk of precipitating scleroderma renal crisis (accelerated hypertension and acute kidney failure)
- angiotensin converting enzyme inhibitors (ACEIs)—prophylactic treatment (for hypertension and kidney disease) with ACEIs can be harmful in systemic sclerosis and is not recommendedKowal-Bielecka, 2017 [NB1] [NB2]
- beta blockers—avoid beta blockers because they can exacerbate peripheral vascular compromise in people with Raynaud phenomenon and digital ischaemia [NB2]
- diuretics—avoid using diuretic drugs to treat hypertension as they can compromise peripheral perfusion
- angiotensin II receptor blockers (ARBs)—appear to be safe for the treatment of essential hypertension but not for scleroderma renal crisisButikofer, 2020.
NB1: ACEIs are the drugs of choice for treating scleroderma renal crisis but are harmful if used for prophylaxis.
NB2: Avoid ACEIs and beta blockers for treating essential hypertension in people with systemic sclerosis.