Dirt-like hyperpigmented plaques on the neck and linea alba of a 12-year-old girl

الملخص EN

-12-year-old girl was referred to the outpatient dermatology department at the Hospital Alto Guadalquivir, Andújar, Spain, in April 2015 with a five-month history of asymptomatic dirt-like hyperpigmented plaques on her neck and linea alba [Figure 1].

The patient had been previously treated with adapalene 0.1% cream twice a day for one month after the eruption was diagnosed as pseudoacanthosis nigricans by a general paediatrician.

However, no response to treatment was observed.

Diabetes mellitus and insulin resistance were ruled out as causative factors and the patient’s medical history was unremarkable.

A dermoscopic examination using the Dermlite DL3 (3 Gen Inc, San Juan Capistrano, California, USA) revealed polygonal areas of brownish pigmentation affecting the dermatoglyphs [Figure 2].

Complete and immediate resolution of the plaques was noted after firm rubbing with a 70% isopropyl alcohol swab [Figure 3].