HSG Treatment Approach

Tinea unguium is the most common of four types of toenail onychomycosis. The toenail bed is the primary site of fungal invasion, although the matrix and nail plate are implicated as well. Pathogenic fungi (“dermatophytes”) invade the nail bed from the distal free edge, referred to as the hyponychium, and advance lengthwise to the lunula causing destruction of the nail plate along the way. Clinical signs include yellow-brown discoloration, thickened nails and longitudinal streaks and striae. If left untreated, this chronic condition will worsen over the years, eventually causing damage to the entire nail unit.

When treating tinea unguium pharmacologically, the antifungal must reach the nail bed in adequate therapeutic concentrations to kill dermatophytes, allowing newly formed nail produced in the matrix to grow out disease-free. Oral medications accomplish this through systemic delivery but are associated with drug interactions and liver toxicity. Most patients seeking to avoid these side effects opt for topicals, especially the elderly. But these formulations (lacquers & solutions), self-applied onto the nail by brush applicator, only work on mild infection and usually after a year of continuous daily application. Patients with moderate to severely infected toes have the toughest challenge as their nails become dystrophic over time and are worsened by trauma, co-morbidities and dermatophytoma.

Once FDA approved, HSG would represent a new treatment option for mild-to-severe fungal infected toes. A physician applies the gel by means of a syringe applicator directly onto the mycotic nail bed providing high fungicidal activity at the infection site and eventual resolution of the disease. It is anticipated that the atraumatic procedure will take less than three minutes and be well tolerated by patients.  Podiatrists, who treat the most patients, are expected to be high adopters and may use other adjunct procedures such as debridement in the toughest of cases.