Most common pattern of onychomycosis is?

Ans. is 'a' i.e., Distal and lateral subungual Clinical subtypes of onychomycosisDistal and lateral subungual onychomycosis (DSO)* DSO is the most common form (90%) of onychomycosis.* Characterized by invasion of the nail bed and underside of the nail plate beginning at the hyponychium and migrates proximally through the underlying nail matrix* DSO is usually caused by the dermatophyte T. rubrum.* Infection of the toenails being much more common than infection of the fingernailsProximal subungual onychomycosis (PSO)* PSO is also known as proximal white subungual onychomycosis (PWSO), a relatively uncommon subtype, and occurs when organisms invade the nail unit via the proximal nail fold through the cuticle area, penetrate the newly formed nail plate, and migrate distally* T. Rubrum is the principal causative agent.* itis common in AIDS patients considered an early clinical marker of HIV infectionWhite superficial onychomycosis (WSO)* WSO is the 2nd most common type (10%)* Fungi invade the superficial layers of the nail plate directly* It can be recognized by the presence of well-delineated opaque "white islands" on the external nail plate, which coalesce and spread as the disease progresses.* Nail is rough, soft, and crumbly* Primarily in the toenails* The most common etiologic agent in is T. mentagrophytesNote - total dystrophic onychomycosis (TDO) is the end result of other three types, if they left untreated.