Rare Cutaneous Side Effects of Imiquimod: A Review on Its Mechanisms, Diagnosis, and Management

Imiquimod, a drug used for various skin conditions, can cause rare cutaneous side effects such as vitiligo, psoriasis, erosive pustular dermatosis, and erythema multiforme. The drug's effects are due to its direct immunomodulation effects on the skin. It can also cause systemic adverse effects like nausea and diarrhea. The mechanisms underlying imiquimod-induced pigment changes are not fully understood, but it can lead to a loss of function and a decrease in the number of melanocytes. Hypopigmentation or depigmentation is typically irreversible and may spread. Imiquimod can also trigger or exacerbate psoriasis and induce erythema multiforme and Stevens–Johnson Syndrome. The document also discusses rare adverse effects like Lupus Erythematosus-like reactions, Pemphigus, Pityriasis Rubra Pilaris, Erosive Pustular Dermatosis of the Scalp, and Lichen Planus. There have been three cases of hair loss related to the topical application of Imiquimod, which was reversible. The document concludes by emphasizing the importance of regular long-term clinical follow-up for patients using Imiquimod due to the potential development or progression of skin tumors.