What should you know about psoriasis and nail changes?

Psoriasis can affect fingernails and toenails, causing pits, discolouration, thickening, separation, or crumbling; a clinician can distinguish these changes from infection or injury and discuss treatment. Nail psoriasis may occur with skin plaques, but nail changes can also be the most noticeable sign. The affected nail may grow slowly and look uneven while the condition is active.

Psoriasis develops through inflammation in the skin and can involve the nail matrix, where the nail is formed, or the nail bed beneath the visible nail. Matrix involvement can create small depressions, grooves, or rough texture. Nail-bed involvement may cause yellow-brown colour, a crumbly area, or lifting from the skin underneath. Several conditions can look similar, including fungal infection, repeated pressure, picking, and some medicines or other skin disorders. A photograph alone may not identify the cause, especially when a nail is thickened or partly detached. A clinician may examine the surrounding skin and, when needed, test nail material before choosing treatment. Psoriasis itself is not spread by touching another person.

Keep nails trimmed, but do not cut into the corners or pull away a lifted section. Use gloves for wet work, cleaning, or tasks that could injure the fingertips, and avoid biting, scraping, or pushing back the cuticles. Moisturise the hands, fingertips, and surrounding skin after washing; this can reduce dryness and cracking around the nail. Comfortable, well-fitting shoes can limit repeated pressure on toenails. Arrange a dermatology assessment if changes persist, involve several nails, or return after an injury has healed. Treatment may include medicine applied to the nail or nearby skin, injections, light-based treatment, or medicine that works throughout the body, depending on the extent and other psoriasis symptoms. Do not start an antifungal treatment solely because a nail is yellow or thickened.

Book a clinical review for a new or unexplained nail change, pain, swelling, tenderness, discharge, or a nail that is lifting. Seek prompt medical attention if redness or swelling spreads around the nail, the finger or toe becomes very painful, or you develop fever. An urgent assessment is also sensible after a significant crush injury or when a dark mark does not grow out with the nail. These features do not prove a serious cause, but they need examination rather than home treatment alone. If nail changes occur with painful, stiff, or swollen joints, mention this soon because psoriasis can affect joints as well as skin and nails.

Ask whether the appearance fits nail psoriasis, infection, injury, or another condition, and whether a nail sample is needed. You can also ask which treatment is appropriate for the nail matrix or nail bed, how long improvement may take as the nail grows, and how to protect the nail during daily tasks. Tell the clinician about skin plaques, scalp symptoms, joint stiffness, recent injuries, and any products or medicines used on the nail.