Trichodysplasia spinulosa associated with chemotherapy for acute lymphocytic leukaemia

We report two boys with trichodysplasia spinulosa associated with chemotherapy for acute lymphocytic leukaemia. Trichodysplasia spinulosa is a cutaneous viral infection of immunosuppressed patients that causes abnormal hair follicle maturation. Our patients presented with widespread papules, some extruding a central keratin spicule, which were most prominent on the face. Histopathology demonstrated hair follicles dilated by a proliferation of large eosinophilic cells containing numerous abnormal trichohyaline granules. Electron microscopy in case 1 revealed 30-nm viral particles in the stratum corneum consistent with a papovavirus. In case 1, the eruption persisted despite topical salicyclic acid 4%, ammonium lactate 17.5%, tretinoin 0.05% and oral acitretin. However, it resolved once the patient's immune function returned to normal (total duration of 2 years). In case 2, the eruption spontaneously resolved after 9 months. This case report discusses the characteristic clinicopathological features of trichodysplasia spinulosa and, for the first time, follows the condition's natural history.