Observations of Psoriasis in the Absence of Therapeutic Intervention Identifies Two Unappreciated Morphologic Variants, Thin-Plaque and Thick-Plaque Psoriasis, and their Associated Phenotypes

Abstract

Psoriatic plaque thickness is a clinical measure of psoriasis severity. We have observed that patients tend to revert to a baseline thickness of psoriatic plaques when in an untreated state, and hypothesized that other features of psoriasis could associate with this trait. Data prospectively collected on 500 participants in the Utah Psoriasis Initiative were used for the study. In response to a question assessing plaque thickness when disease was at its worst, 144 (28.8%) reported thick plaques, 123 (24.6%) reported thin plaques, and 233 (46.6%) reported intermediate thickness. For patients with "worst-ever" disease at enrollment (n=122), there was significant correlation of thickness between assessment by the patient and the physician (r=0.448, P-value 0.01). Thick plaques associated with male gender, increased body mass index, nail disease, psoriatic arthritis, larger plaques, more body sites, and greater total body surface area affected. Thin plaques associated with eczema, guttate psoriasis, and skin cancer. We suggest that this is preliminary evidence that plaque thickness is an easily measured trait that associates with other clinical features of psoriasis, and that stratification on this phenotype may be useful in further defining the genetic basis of this disease.

Excessive Body Weight and Smoking Associates with a High Risk of Onset of Plaque Psoriasis

“…PASI might be affected by increased body surface area in very obese individuals; however, in our study we had only 3 cases with BMI >40, one in each PASI group. Previous studies of established chronic psoriasis have shown positive association between increased relative body weight and disease activity; risk estimates varied from OR=3.0 (95% Cl 1.5-6.0) to 0R= 1.7 (95% Cl 1.6-1.9) when comparing obesity with normal weight (7,9,33).…”

“…Psoriasis was classified into phenotypic subsets, such as plaque, guttäte or other phenotypes representing palmoplantar, pustular, erythrodermic and inverse psoriasis (27). Diagnosis of psoriatic arthritis was completed by a rheumatologist following established criteria (33).…”

Guidelines of care for the management of psoriasis and psoriatic arthritis

“…Because of the lack of sufficient data, however, it is difficult for the clinician to make definitive recommendations regarding the proper sequence or duration of therapies that should be used to treat patients with moderate to severe PsA. 191,192 3. For identified risk factors (eg, smoking, alcohol, and obesity) data are necessary to determine if modification of these risk factors will prevent psoriasis or modify its severity.…”

Vascular endothelial growth factor (VEGF) in the pathogenesis of psoriasis—A possible target for novel therapies?

“…As a result, the epidermis is thickened (acanthosis), with elongated rete ridges. In combination with the dermal inflammatory infiltrate, this contributes to the overall appearance of the lesions, which can vary between thick and thin plaque psoriasis and has been proposed as a distinctive trait of the disease [1,6]. The inflammatory infiltrate consists mainly of dendritic cells, macrophages and T cells in the dermis and neutrophils, with some T cells, in the epidermis.…”