Localization of Treatment-resistant Areas in Patients With Psoriasis on Biologics

K.F. Hjuler; L. Iversen; M.K. Rasmussen; K. Kofoed; L. Skov; C. Zachariae


The British Journal of Dermatology. 2019;181(2):332-337. 

In This Article


Study Participants

A total of 146 patients with well-treated moderate-to-severe psoriasis were included in the study. Table 1 shows the characteristics of the included study participants.

Body Locations of Treatment-resistant Psoriasis

The most common site of recalcitrant psoriasis in this cohort of patients treated with biologic agents was the anterior lower leg region [49·3%; 95% confidence interval (CI): 41·2–57·4]. Further common sites of recalcitrant psoriasis were the posterior lower leg region (24·7%; 95% CI 17·7–31·6), the elbow region (35·6%; 95% CI 27·8–43·4), and the scalp (19·2%; 95% CI 12·8–25·6%) (Figure 1) (Table S1, for full dataset including proportions; see Supporting Information).

Figure 1.

Distribution of recalcitrant psoriasis among all included patients (n = 146).

In the body regions traditionally considered as difficult-to-treat entities, the proportion of patients with recalcitrant psoriasis were: fingernails 13·0% (95% CI 7·6–18·5), toenails 11·0% (95% CI 5·9–16·0), scalp 19·2% (95% CI 12·8–25·6), palmar region 3·4% (95% CI 0·5–6·4), plantar region 1·4% (95% CI –0·5 to 3·3) and intertriginous areas 10·3% (95% CI 5·3–15·2).

Overall, the patients had a low DLQI (Table 1). Among patients where the psoriasis was considered not to have an influence on their quality of life, defined as patients with low DLQI of 0–1 (n = 79), the most common sites of recalcitrant psoriasis were the scalp, elbows, knees, and anterior and posterior lower legs (Figure 2a). Among patients with moderately elevated DLQI of 2–5 (n = 55), the most common sites of recalcitrant psoriasis were the elbows, dorsal forearms, posterior thighs, and posterior and anterior lower legs (Figure 2b). Among patients with DLQI > 5 (n = 12), the most common locations of recalcitrant psoriasis were fingernails, elbows, lower back, and anterior and posterior lower legs (Figure 2c). No statistically significant association between DLQI and the distribution of affected areas were observed. After adjustment for multiple comparisons, there was no association between residual psoriasis in any particular area and DLQI.

Figure 2.

Distribution of recalcitrant psoriasis among patients with (a) Dermatology Life Quality Index (DLQI) 0–1 (n = 79), (b) DLQI 2–5 (n = 55) and (c) DLQI > 5 (n = 12).