Dermatology - Nail Psoriasis

Dermatology - Nail Psoriasis 

The most prevalent dermatosis that affects the nail apparatus is psoriasis, which affects the nails in >50% of cases, up to 80–90% of cases over the course of a lifetime.

Elkonyxis, also known as pitting, will be present in the nail matrix. These small, shallow punctate depressions come in a variety of sizes and shapes. Though they can also occur as regular lines (transverse; long axis) or in grid-like patterns, their characteristics are isolation and depth.
Lesions in the toenails are rare. The nail is rough, brittle, and dull. Proximal nail matrix destruction is linked to sandpaper nails, or twenty-nail dystrophy; however, this is general and can also be observed in alopecia areata, lichen planus, and atopic dermatitis. 

Repeated transverse depressions may resemble the "washboard" nails of tic habits, where the cuticle is pushed back.
Longitudinal ridging, akin to melted wax, could exist. One or two millimeter white spots in the nail plate called punctate leukonychia are sometimes misdiagnosed as injuries.
An oval, salmon-colored nail bed called "oil" patches may be present, and onycholysis may develop as a result, affecting the hyponychium medially or laterally.
There could be secondary infections. Subungual hyperkeratosis, or raising of the nail plate off the hyponychium, is possible.

A clinical exam and history are used to make a diagnosis. Onycholysis, onychomycosis, trauma (toenail), eczema, and alopecia areata are among the differential diagnoses.

Intralesional triamcinolone 3-5 mg/mL may be useful for matrix involvement. Topical steroid (occluded) decreases hyperkeratosis in nail bed psoriasis. Nail apparatus psoriasis is frequently improved by systemic therapy, such as methotrexate, acitretin, or "biologics," though results may not show up for some months after treatment has finished.