While drug induced lupus is well recognised, lupus patients are also at risk of disease exacerbations due to certain drugs. There is a long list of drugs associated with drug induced lupus and it behoves the clinician to be aware that a lupus disease flare may just be due to a newly introduced drug. Examples include terbinafine, antihypertensives, long-term use of tetracyclines and proton pump inhibitors such as omeprazole. Cutaneous lesions are the most frequent presentation often in the absence of systemic symptoms and drug withdrawal usually results in rapid resolution.

Conditions related to lupus

Primary Sjögren's Syndrome is the most common autoimmune rheumatic disease after rheumatoid arthritis. Most patients present with symptoms of dryness in the eyes and mouth and there can be systemic symptoms including fatigue, joint pains, lymphadenopathy and glandular swelling especially of the parotid and submandibular glands.
Sjögren's Syndrome is characterised by the presence of antibodies to Ro and La, rheumatoid factor, high immunoglobulin G level and elevated ESR but with normal CRP. Lupus patients commonly develop secondary Sjögren's Syndrome with dry eyes and dry mouth symptoms, especially in the presence of the antibodies most commonly associated with Sjögren's Syndrome, namely anti Ro and anti-La antibodies.
Dermatomyositis may be misdiagnosed as lupus as both conditions may present with photosensitive skin rashes and aches and pains. Muscle inflammation may be absent in the early phases of dermatomyositis and, confusingly, skin biopsies from dermatomyositis patients may be indistinguishable from lupus. The myositis autoantibody panel which includes myositis specific and myositis associated antibodies is increasingly useful in distinguishing these two autoimmune diseases.
Overlap autoimmune rheumatic diseases may be confused with lupus although these patients are more likely to have Raynaud's Phenomenon and antibodies to RNP may be detected in the serum.

Fatigue and Fibromyalgia

Fatigue is almost universal in patients with all the autoimmune rheumatic diseases and is a major contributor to impaired quality of life. The pathogenesis of chronic and severe fatigue in lupus is multifactorial and may be due to active disease as well as other factors such as anaemia, renal failure, hypothyroidism and physical deconditioning. Depression and poor sleep patterns are commonly associated with severe fatigue. Rather frustratingly for patients, fatigue often persists even when the lupus is in remission. Treatment is unsatisfactory and revolves around controlling disease activity, regular exercise and dietary measures to reduce weight gain. Fibromyalgia or chronic widespread pain may develop in 10-15% of lupus patients and, like fatigue, can be difficult to assess and treat. The treatment of chronic widespread pain is very different to that of lupus and may include graded exercise, cognitive behavioural therapy and low-dose tricyclic agents such as Amitriptyline.

Summary

Lupus is a complex disease and patients benefit most from a multidisciplinary approach. A chronic disease management strategy aiming to prevent or minimise disease flares, complications and damage accumulation will ultimately improve quality of life, reduce morbidity and reduce the risk of premature mortality.