Duarte Flor, Dermatovenereology Department, Coimbra Hospital and University Centre, Coimbra, Portugal Ricardo Vieira, Department of Dermatology, Coimbra University Hospital, Coimbra, Portugal

Onychocryptosis is an inflammatory disease of the lateral nail fold resulting from the embedding of the lateral border of the nail plate in the periungual soft tissues with consequential formation of granulation tissue and hypertrophy of the lateral nail fold. Therapeutic options include conservative and surgical strategies. There is no consensus regarding the strategy to be adopted at each stage of severity. The bibliographic research for the elaboration of this paper was obtained through PubMed and ClinicalKey platforms. Review articles, scientific articles and descriptions of clinical cases were selected. After careful and critical analysis of the selected articles, the present literature review was carried out. The therapeutic choice for each stage of onychocryptosis is complex. Conservative treatment is safe, convenient, and inexpensive, yet it only has proven efficacy in stage I. Matricectomy with phenol or other agents after partial nail avulsion proved to be safe, inexpensive, and effective, thus being the first line in the treatment of stages II or III. Soft tissue resection techniques proved to be effective in cases of marked hypertrophy of the nail folds but are more invasive and lead to a longer recovery period. In such cases, it is recommendable to perform a resection of the periungual soft tissues, with Howard-Dubois, Vandenbos and Super U techniques being the most effective and chosen according to the location and severity of the hypertrophy of the nail folds. When treating onychocryptosis, the conservative approach is indicated for stage I, while surgical treatment is indicated for stages II and III. The first line in stages II and III should be 88% phenol solution matricectomy. New prospective comparative studies and randomized trials are necessary to implement a standardized clinical approach.

Keywords: Onychocryptosis. Ingrown nail. Nail surgery. Matricectomy.