Successful management of recalcitrant cutaneous warts with low-dose acitretin monotherapy in a patient with idiopathic CD4 lymphocytopenia.

A 50-year-old man with a background of idiopathic CD4 lymphocytopenia (ICL) was successfully treated with acitretin monotherapy for recalcitrant viral warts on the hands and right cheek. Treatment duration was 35 months, with sustained effects at 15 months post-acitretin therapy. Side-effects were mild and included mild cheilitis and dryness of nasal mucosa. CD4 lymphocytes play an important role in enabling host responses to human papillomavirus (HPV) and, consequently, lower CD4 counts correspond to a higher risk of chronic HPV infection, including viral warts. HPV represents the most common opportunistic infection in patients with ICL. Acitretin is an oral retinoid with affinity for retinoic acid and retinoid X receptors, and works through downregulation of signal transducer and activator of transcription (STAT)1- and STAT3-dependent signalling, with resultant increases in keratinocyte differentiation. As HPV evades the Janus kinase/STAT pathway to promote keratinocyte proliferation, acitretin may work through reversal of this mechanism. This case demonstrates effectiveness of acitretin in treating recalcitrant viral warts, specifically in a patient with ICL.