Introduction

Genital lesions may be the exclusive manifestation of psoriasis in 2–5% of cases. Clinical features of balanoposthitis are often non-specific, and dermatoscopy can help differentiate psoriasis from other genital conditions. Reportedly, dermatoscopic features of psoriatic balanoposthitis are limited to uniformly distributed dotted vessels on a light red background, while treatment of genital psoriasis is challenging.

Objective

The aim of this report was to focus on potentially underreported dermatoscopic features of psoriatic balanoposthitis and to evaluate treatment response using dermatoscopy.

Material and methods

Dermatoscopic images of histopathologically confirmed psoriatic balanoposthitis (n = 16) were acquired before and after a 3-week treatment course with tacrolimus 0.1% ointment. Histopathological features of psoriatic balanoposthitis were correlated with dermatoscopic features. The severity of psoriatic balanoposthitis was dermatoscopically graded before and after treatment and compared using the Wilcoxon signed-rank test. A p-value < 0.05 was considered statistically significant.

Results

Pustules were observed dermatoscopically in 5/16 (31.25%) patients with psoriatic balanoposthitis, while clinical examination revealed pustules in only 3 cases. This dermatoscopic feature corresponded to Kogoj’s spongioform pustules on histopathology. Uniformly arranged dotted vessels were observed in all cases and corresponded to dilated, tortuous vessels within elongated dermal papillae. Fine scaling was observed dermatoscopically in 6/16 (37.50%) cases. The severity of psoriatic balanoposthitis significantly decreased after treatment with topical tacrolimus (p < 0.001).

Conclusions

Persistent dotted vessels of decreased diameter were a dermatoscopic sign of incomplete response to treatment. Dermatoscopy can facilitate visualization of pustules in psoriatic balanoposthitis when they are not clinically apparent.