Eosinophils Among the Histological Features of Psoriasis

Abstract

Eosinophils are absent in psoriasis" has been dogma for generations; yet, there is little published to support this statement. Two recent studies examining the presence of eosinophils in psoriasis came to contrasting conclusions. We reviewed skin biopsies from 50 patients with clinically confirmed cases of psoriasis vulgaris to characterize the histologic features, with a focus on the number of eosinophils in the dermis. We noted the presence of eosinophils in nearly half of our study population (n = 23, 46.0%). There was no significant association between the presence of eosinophils and degree of spongiosis (P = 0.405). Eosinophil density ranged from 0 to 8 per tissue section. The mean average eosinophil density was 1.04 (range: 0-8) per tissue section. Among cases with eosinophils, there were 73.9% (n = 17/23) of cases with 1-2 eosinophils, and 26.1% (n = 6) with 3-8 eosinophils. Mild to moderate spongiosis was noted in the majority of cases (n = 48; 96.0%). Eosinophils were only present in psoriasis cases with evidence of spongiosis (n = 23; 47.9%). We conclude that eosinophils are not an uncommon finding in the dermis of psoriasis vulgaris, although the number is often few. The presence of eosinophils should not preclude a diagnosis of psoriasis, particularly if other histologic features are supportive.

Histopathologic features of inverse psoriasis

“…[9][10][11] Prior studies have observed dermal eosinophils present in 46% and 49% of their patients, respectively. 9,11 These studies used different methods to quantify the number of eosinophils present.…”

“…In addition, total number of dermal eosinophils per tissue section was quantified in line with prior studies examining eosinophils in psoriasis. 9,10 Inflammatory cells present within vessels were excluded from all counts. All other categories were characterized by presence vs absence of each feature (Table 2).…”

“…1,[6][7][8] Spongiosis occurs but is generally mild, and although prior dogma asserting the absence of eosinophils in psoriasis has been questioned, eosinophils are still thought to be rare when present. 9,10 The diagnosis of inverse psoriasis is often made clinically but can prove challenging in the absence of other skin lesions typical to psoriasis. A skin biopsy is generally performed when lesions fail to respond to conventional treatment or if an alternative diagnosis mimicking inverse psoriasis is considered-such as frictional intertrigo, contact dermatitis, lichen planus, seborrheic dermatitis, fungal infections because of dermatophytes or Candida spp., erythrasma, and other superficial bacterial infections from Staphylococcus aureus, Streptococcus spp., Pseudomonas spp., or Proteus spp.…”

Identification of a TH2‐high psoriasis cluster based on skin biomarker analysis in a Chinese psoriasis population

“…All of them were observed positively correlated with several T H 2‐related and T activation markers, a reasonable explanation for strong T H 2 component in cluster 1. It had been acknowledged that eosinophils were absent in psoriasis, 28 and however, recent studies revealed that eosinophils are not uncommon in the dermis of psoriasis and might accelerate psoriatic inflammation by supporting an inflammatory milieu that promotes neutrophil infiltration 29,30 . Therefore, the presence of eosinophils might be an indicator of neutrophil infiltration, rather than a T H 2‐skewed feature.…”

Drug Reactions

“…Vyas and coworkers conducted a detailed comparison of AGEP and pustular psoriasis [125]. They demonstrated a significant association between AGEP and the presence of eosinophils, although single necrotic keratinocytes as well as eosinophils were seen in both diseases, and sparse dermal eosinophils are a well-documented finding in psoriasis [126][127][128]. There was a tendency for AGEP to exhibit both subcorneal and deeper intraepidermal pustules, whereas pustular psoriasis showed mostly subcorneal pustules.…”