Psoriasis is a common and recurring chronic inflammatory skin disease. Skin lesions can occur all over the body, with the scalp and extensor surfaces of the limbs being the most common. Fingernails and mucous membranes can also be invaded. In recent years, with the improvement of people’s living standards, more and more attention has been paid to psoriasis on exposed areas. In addition to affecting beauty, nail psoriasis seriously affects the patient’s ability to live, and therefore receives wide attention. 1. Epidemiology and associated factors of nail psoriasis Patients with psoriasis, about 5.1 million in Europe and 7 million in the United States, have nail involvement in 15%-50% of psoriasis patients. In some clinical studies this percentage can be as high as 80%, and 1-5% of patients have nail involvement without skin manifestations. Approximately 80% of patients with psoriatic arthritis have nail involvement. Nail involvement is positively correlated with the duration of psoriasis and the size of the lesions; the incidence is higher in patients with psoriatic arthritis; severe cases are associated with tendonitis, polyarthropathy, and persistent, progressive arthritis. 2. nail differentiation and anatomy nails are appendages of the skin – developmentally, nails occur from the epidermis11 , however, recent histological studies have shown that nails are integrated with the musculoskeletal system However, recent histological studies have shown that the nail is integral to the musculoskeletal system – functionally connected to the distal phalanges and distal interphalangeal structures. The anatomy of the nail is shown in Figs. 1-3. Fig. 1 Frontal and sectional views of the nail (extensor tendon starting and ending points) Fig. 2 Sagittal section of the distal interphalangeal joint (DIP), (Masson’s trichrome stain) showing the fibrous tissue surrounding the nail root at the starting and ending points of the extensor tendon Fig. 3 The main clinical manifestations of nail psoriasis are mainly the nail bed and nail plate Involvement, see Figure 4-Figure 6 Figure 4 Main clinical features of nail psoriasis Figure 5 Characteristic manifestation of nail bed Figure 6 Characteristics of nail mother involvement Figure 7 Psoriatic nail furuncle Figure 8 Psoriatic nail-skin hypertrophy-periostitis (POPP syndrome)