Patients with bullous pemphigoid and comorbid psoriasis present at a younger age with bullous pemphigoid of a more severe erosive phenotype and higher levels of pathogenic autoantibodies, compared with patients with bullous pemphigoid and without psoriasis, according to study findings published in the Journal of the European Academy of Dermatology and Venereology.
Researchers conducted a retrospective cohort study of 273 consecutive patients diagnosed with bullous pemphigoid from 2009 to 2019 at a tertiary referral center. A total of 11 patients (4%; 95% CI, 2.3%-7.1%) had comorbid psoriasis, for which the onset preceded that of bullous pemphigoid in 81.8% of this group by a median latency of 26.5 years (range, 5-34 years). Within the cohort, 119 (43.6%) participants were men; average age at diagnosis was 79.1±9.9 years, and median age was 80.4 years (49.6-98.2 years).
Compared with patients with bullous pemphigoid and without psoriasis, those with bullous pemphigoid and comorbid psoriasis were significantly younger at the onset of bullous pemphigoid (71.8±9.3 vs 79.4±9.8 years; P =.023), had a milder erosive phenotype (erosion/blister Bullous Pemphigoid Disease Area Index [BPDAI] mean score; 5±4.1 vs 22.3±15.2; P =.025), lower levels of anti-BP180 NC16A serum autoantibodies (236.6±266.3 vs 556.2±1323.6 U/ml; P =.008), a higher prevalence of isolated linear C3 deposits (36.4% vs 14.1%; P =.043), and a lower prevalence of linear immunoglobulin G deposits (36.4% vs 68.7%; P =.025) along the dermal-epidermal junction according to direct immunofluorescence microscopy.
“No differences were revealed between both subgroups in the severity of the erythematous phenotype (as estimated by urticaria/erythema BPDAI) or in the pruritus and damage components of the BPDAI score,” the investigators commented. “It is noteworthy, the BPDAI score was systematically evaluated in 48.4% (n=132) of the study population. The 2 compared subgroups were comparable with regard to the prevalence of the main metabolic, cardiovascular, and neurological comorbidities as well as in the distribution of different therapeutic interventions.”
The study authors also noted that the retrospective data collection resulted in missing information for some variables and that selection bias cannot be refuted because the study was held in a tertiary-care referral center that specialized in autoimmune bullous diseases.
“Further research is warranted to elucidate the pathomechanisms of this association and to validate the distinct clinical and immunopathological profile of these patients in other study populations,” the researchers concluded.
Ständer S, Schmidt E, Zillikens D, Thaçi D, Ludwig RJ, Kridin K. Patients with bullous pemphigoid and comorbid psoriasis present with less blisters and lower serum levels of anti-BP180 autoantibodies. Published online October 24, 2020. J Eur Acad Dermatol Venereol. doi: 10.1111/jdv.17013