Bullous pemphigoid is an acute or chronic autoimmune disease of the skin, involving the formation of blisters in the skin layers. It is can be a very disabling disease and is unsightly. As a general medical registrar I remember looking after several patients with severe BP. One patient died under our care with secondary infection and septicaemia. On occasions when the disease is extensive with many lesions that slough patients can lose a lot of liquids and salts or electrolytes through the lesions, which adds to difficulties in managing them.
The Danish registry study shows a surprising association between BP and MS; pwMS are almost 10x more likely to develop BP than the general population. Why?
I have another interest in BP in that it is one of the potential secondary autoimmune diseases that may develop post-alemtuzumab. I am aware of one pwMS who developed BP after being treated with alemtuzumab. So please be vigilant if you have had alemtuzumab treatment and develop any blistering of the skin please seek medical attention ASAP. The cause of BP is an auto-antibody that binds to a particular protein in the skin. BP is therefore another one of the many emerging auto-antibody mediated secondary autoimmune diseases that may develop post-alemtuzumab.
It is a great pity we didn’t test our hypothesis of trying to prevent autoimmune disease post-alemtuzumab; i.e. with a small dose of rituximab, or using teriflunomide, after alemtuzumab. If successful can you imagine what a difference it would have made regarding the use and uptake of alemtuzumab as a treatment for MS? We have had to abort our ideas of doing any trials of this nature; with the emergence of the next generation of DMTs, i.e. ocrelizumab and oral cladribine, it is likely that most patients will not choose alemtuzumab as a treatment. I predict alemtuzumab will become the MS treatment of last resort, being used just prior to HSCT.
Kibsgaard et al. Increased frequency of multiple sclerosis among patients with bullous pemphigoid: a population-based cohort study on comorbidities anchored around the diagnosis of bullous pemphigoid. Br J Dermatol. 2017 Jun;176(6):1486-1491.
BACKGROUND: Bullous pemphigoid (BP) is a disease of the elderly and may be associated with neurological and cardiovascular diseases and diabetes. Mortality rates strongly exceed those of the background population.
OBJECTIVES: To investigate the frequency of comorbidities and their temporal relation to BP.
METHODS: A register-based matched-cohort study on all Danish patients with a hospital-based diagnosis of BP (n = 3281). The main outcomes were multiple sclerosis (MS), Parkinson disease (PD), Alzheimer disease (AD), stroke, diabetes types 1 and 2, malignancies, ischaemic heart disease (IHD), hypertension and eventually death.
RESULTS: At baseline, patients with BP had increased prevalences of MS [odds ratio (OR) 9·7, 95% confidence interval (CI) 6·0-15·6], PD (OR 4·2, 95% CI 3·1-5·8), AD (OR 2·6, 95% CI 1·8-3·5) and stroke (OR 2·7, 95% CI 2·4-2·9). Furthermore, malignancies, cardiovascular disease and diabetes were over-represented among patients with BP: type 1 diabetes (OR 3·1, 95% CI 2·5-3·8), type 2 diabetes (OR 2·3, 95% CI 2·0-2·6), malignancies (OR 1·3, 95% CI 1·1-1·4), IHD (OR 1·7, 95% CI 1·5-1·9) and hypertension (OR 2·0, 95% CI 1·8-2·2). During follow-up, the risk of MS was significantly higher among patients with BP [hazard ratio (HR) 9·4, 95% CI 4·9-18·0], even if events during the first year after diagnosis of BP were excluded (HR 5·1, 95% CI 2·3-11·3). Patients with BP had an average increased mortality rate of 2·04 (95% CI 1·96-2·13).
CONCLUSIONS: We discovered a significantly increased frequency of MS among patients with BP. At the time of diagnosis, patients with BP had an excessive number of comorbidities and an increased mortality rate over the following years.