Shedding Light on the “Hidden Psoriasis”: A Pilot Study of the Inverse Psoriasis Burden of Disease (IPBOD) Questionnaire

August 2016 | Volume 15 | Issue 8 | Original Article | 1011 | Copyright © August 2016

Jeffrey M. Cohen BA,1,* Kareem Halim AB,1,* Cara J. Joyce MS,2 Mital Patel MD,3 Abrar A. Qureshi MD MPH,4 and Joseph F. Merola MD MMSc3,5

1Harvard Medical School, Boston, MA
2Department of Biostatistics, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA
3Department of Dermatology, Harvard Medical School, Brigham and Women’s Hospital, Boston, MA
4Department of Dermatology, Warren Alpert Medical School, Brown University, Providence, RI
5Department of Medicine, Division of Rheumatology, Harvard Medical School, Brigham and Women’s Hospital, Boston, MA
*These authors contributed equally to this work

While burden of disease (BOD) data exists for plaque psoriasis, and to a lesser extent other phenotypes of psoriasis, there is no published data on the impact of inverse (intertriginous) psoriasis. We sought to assess the overall BOD among patients with inverse psoriasis (IP). We introduce the Inverse Psoriasis Burden of Disease (IPBOD) questionnaire and compare it to the Dermatology Life Quality Index (DLQI). In this cross-sectional pilot study, we administered the IPBOD and the DLQI to 16 patients. We present the initial psychometric properties of the IPBOD survey. We used Spearman’s correlation coefficients to compare the two questionnaires on overall performance and in specific domains. Our cohort had an average age of 55.6 (SD 16.6) years, was predominantly female (68.8%), and white (87.5%). 87.5% of patients had a second psoriasis subtype. A majority of patients reported some effect of IP on pain (n=14, 87.5%). Thirteen (81.3%) patients reported some effect on depressed mood or anxiety/worry. Overall, the largest effect was on body self-image (93.8% reporting an effect). The average DLQI score was 8.5/30, higher than average DLQI scores reported in patients with plaque psoriasis or psoriatic arthritis. Average IPBOD score was 4.9/10. The reliability of IPBOD was good (overall Cronbach’s alpha = 0.89, individual items’ range 0.88 – 0.91). Correlations between IPBOD and DLQI were: overall (Spearman’s P=0.650, P=0.006), symptoms (P=0.462, P=0.072), daily activities (P=0.507, P=0.045), leisure (P=0.633, P=0.008), interpersonal function (P=0.728, P=0.001), and work and school (P=0.427, P=0.100). IP has a profound impact on patients’ lives and the results of this pilot study suggest that the IPBOD questionnaire may be a useful disease-specific tool for measuring the BOD of IP.

J Drugs Dermatol. 2016;15(8):1011-1016.


Psoriasis is a chronic inflammatory skin condition that is estimated to impact 1-3% of the global population. The disease has been shown to negatively impact quality of life.1 Several phenotypic subsets exist including plaque, scalp, nail, palmoplantar disease and intertriginous disease. Inverse (intertriginous) psoriasis involves the skin folds, including the infra-mammary region, axillae, inguinal / groin folds, intergluteal, and other body folds.2 This phenotype of psoriasis is more prevalent than previously recognized and has been found to affect up to 21% of all psoriasis patients (unpublished data). Despite the relatively small body surface area of involvement, lesions in these sites can dramatically impair daily functioning.2 Discussions with inverse psoriasis patients underscore that the disease can limit interpersonal interaction, romance, and important activities of daily living such as toileting and personal hygiene. Moreover, inverse psoriasis has been identified as a risk factor for psoriatic arthritis (HR 2.35).3 Given the personal nature of this disease, patients may feel less compelled to talk about their inverse psoriasis. This produces difficulty in diagnosis of inverse psoriasis. It also makes inverse psoriasis a “hidden psoriasis” and hinders our understanding of the burden of disease associated with the condition.
Multiple questionnaires have been developed to measure the impact of psoriasis on patients’ lives, but most of these are designed for plaque psoriasis.4 There have been several studies addressing quality of life in specific psoriasis subtypes, including scalp, palmoplantar, and nail psoriasis. These studies have found that the subtypes of psoriasis have equal and sometimes even more profound effects on quality of life.5-8 No study has specifically examined the burden of inverse psoriasis. The Brigham scalp, nail, inverse, palmoplantar composite index (B-SNIPI) includes scalp, nail, and inverse psoriasis, but is designed to measure composite severity and does not focus solely on burden of disease on the patient.2 Therefore, understanding the burden of inverse psoriasis on the lives of patients remains an unmet need in the treatment of psoriasis.