Cheilitis: a comprehensive review and a new clinical classification proposal. Part 1: Isolated cheilitis.

Cheilitis refers to an acute or chronic inflammation of the lips. It may occur in isolation, affecting only the vermilion border, or may be associated with oral or perioral involvement. Numerous dermatological and systemic diseases may involve the lips, making the clinical assessment of cheilitis particularly challenging. Various types of cheilitis distinguished by frequency, cause, and duration have been described in the literature. However, there are no univocal recommendations on classification. This article aims to introduce a classification of cheilitis based on etiology, according to the following categories: 1) isolated cheilitis, referring to inflammation confined exclusively to the lips, without systemic manifestations or oral cavity involvement. This group includes cheilitis simplex, contact cheilitis, exfoliative cheilitis, granulomatous cheilitis, glandular cheilitis, plasma cell cheilitis, actinic cheilitis, and infectious cheilitis; 2) cheilitis associated with dermatological conditions that exhibit little to no systemic involvement, such as atopic dermatitis, lichen planus, autoimmune bullous diseases, discoid lupus erythematosus, and psoriasis; 3) cheilitis associated with systemic diseases when lip inflammation occurs in the context of systemic conditions, including systemic lupus erythematosus, orofacial granulomatosis, sarcoidosis, Crohn's disease, Melkersson-Rosenthal syndrome and nutritional deficiencies; and 4) drug-induced cheilitis, when a clear causal relationship is established between drug exposure and lip inflammation, as observed in cases of cheilitis induced by oral retinoids, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, and DRESS (drug reaction with eosinophilia and systemic symptoms) syndrome. This proposed classification may offer clinicians a practical tool for the systematic evaluation and management of patients presenting with cheilitis.