Why does nail psoriasis cause thickened nails?

Psoriasis may affect the nail matrix, which produces the plate, or the nail bed that supports it. Uneven growth can make the plate ridged, thicker or crumbly. If it lifts slightly, keratin can collect underneath and add to the raised appearance. Pits, colour changes and tenderness may occur alongside thickening. Thickened Nails is a common presentation of Nail Psoriasis, yet fungus and repeated trauma can look similar. Looking at other skin or joint symptoms can help a clinician decide whether testing is needed.

Trim the nail carefully when it is manageable and smooth sharp edges with a file. Avoid picking, biting or cutting the cuticle, and wear gloves for prolonged contact with water or cleaning products. Shoes should leave room around thickened toenails. Do not force material out from beneath the plate. A clinician may use a nail treatment, skin treatment or broader psoriasis treatment, depending on which structures are involved.

Seek review if thickening is new, worsening, painful or making daily tasks difficult. Prompt care is appropriate for swelling, warmth, drainage, spreading redness or fever. A dark streak, sudden change in one nail or pigment on nearby skin should be checked rather than assumed to be psoriasis. Report joint swelling, stiffness or pain, as nail psoriasis can occur alongside joint symptoms that need their own assessment.

Which part of the nail is affected? Could fungus or trauma be contributing? Would a sample help? What trimming method and treatment are safest for the nail pattern I have?