We present a case of a 40-year-old female with four years history of widespread rash which had disappeared during her pregnancy and breast feeding period. It reoccurred after breastfeeding was stopped. Her past medical history included IVF, during this time her skin changes remained unchanged.Physical examination showed widespread flat-topped papules 1-2mm in diameter, more prominent on the extensor surfaces of the forearms and trunk.Laboratory tests showed normal FBC, liver and renal function. LDH was within normal level. Autoimmune screen ANA, DsDNA and ENA were negative. Incisional biopsies showed superficial dermal lymphocytic infiltrate and foreign body type granulomas abutting the basal layer of the epidermis. There were no features of eczema, cutaneous T cell lymphoma or keratosis pilaris. The histology was consistent with lichen nitidus.Lichen nitidus is a rare inflammatory skin eruption of unknown cause, which usually affects the upper extremities. The generalised form is even more uncommon. Often no treatment is required and the condition can be self-limiting. To our knowledge there is no previous report of exact cause of Lichen nitidus. There is previous reports that during pregnancy, many women experience remission of autoimmune diseases like multiple sclerosis and uveitis. The pathophysiology is still not well understood, although we know that during pregnancy part of the immune system is downgraded in favour of the growing fetus.As this patients’ skin had completely cleared during pregnancy and breast feeding, we suggest that possibly there may be similar pathophysiology of autoimmune origin involved in Lichen nitidus.
Mona Ebadian, Dhawshini Ravindran, Volha Shpadaruk, Iman Belsalma