Safety and Efficacy of Intralesional 0.5% Triamcinolone Acetonide in 0.2% Fluconazole Solution vs 0.1% Topical Mometasone Furoate With 2% Miconazole Nitrate Cream in the Treatment of Chronic Paronychia: An Intraindividual Randomized Controlled Trial.

Chronic paronychia (CP) is defined as inflammation of the nail fold(s) of more than 6 weeks duration (Shafritz and Coppage, 2014). It is now considered as a form of hand eczema, caused primarily by irritation of the nail folds by environmental allergens. This leads to recurrent inflammation of nail folds, followed by fibrosis and inability to generate the cuticle, ending in loss of the waterproof seal, moisture retention, and compromise of blood supply due to fibrosis. These can explain why CP is commonly resistant to topical and even systemic treatments. Candida infection is thought to be a secondary event in a subset of cases (Relhan and Bansal, 2022), with positive fungal culture in about 56.1% of cases (Bahunuthula et al., 2015) Important risk factors for the development of CP include occupations with excessive exposure to moisture and irritants (e.g. housewives, cooks, and health care providers), immunosuppression (e.g. diabetes mellitus and HIV); due to increased risk of secondary colonization, and some medications (e.g. retinoids) (Relhan and Bansal, 2022). A higher incidence of contact sensitization and Candida hypersensitivity in these patients has been reported, (Bahunuthula et al., 2015) thus candidal control may be of help to ameliorate the disease.

Clinically, CP presents with erythema, pain and swelling of one or more of the nail folds for >6 weeks. It generally affects multiple fingernails, more commonly, of the dominant hand. Nail matrix may be secondarily affected leading to transverse ridging, discoloration, Beau's lines, or onychomadesis (Shafritz and Coppage, 2014, Atiş et al.,2018). The last updated severity scale for CP has been proposed in 2018, taking into account the number of affected nail folds, erythema, edema, nail plate and cuticle changes (Atiş et al.,2018).

Management of CP relies mainly on avoidance of the irritants and topical corticosteroids which are now considered the mainstay of treatment (Shafritz and Coppage, 2014). Systemic antifungals are used in cases with associated candida infection (Tosti et al., 2002).

Intralesional steroid injection, in the form of monthly injections of triamcinolone acetonide (2.5- 10 mg/mL), is used for the treatment of nail psoriasis, nail lichen planus and twenty-nail dystrophy. It is, however, scarcely mentioned in literature in the management of CP (Baran, 2001). In addition, the optimal treatment regimen and injection technique have not yet been established, and no recent relevant studies exist.

Surgical treatment is reserved for cases of CP of more than 6-month duration, that has been resistant to medical treatment (Relhan et al., 2014)