The hardening and thickening of the skin of the finger joints may be caused by long-term friction, lichen planus, gout and other factors. 1. Long-term friction: If there is long-term and excessive friction on the finger joints, it may lead to thickening of the local skin stratum corneum, thus causing the skin to become hard and thickened. 2. Lichen planus: Lichen planus can be manifested as a purplish-red polygonal rash with a waxy glossy surface, which can lead to hardening and thickening of the skin when it occurs on the fingers. 3. Gout: gout patients due to higher than normal levels of uric acid in the body may cause uric acid deposition in the joints and surrounding soft tissues, the diseased parts of the skin can appear hyperpigmentation, thickening of the phenomenon. Finger joint skin hardening and thickening may also exist for other reasons, it is recommended that the patient to the regular hospital dermatology, rheumatology and immunology and other related departments to consult in detail, follow the doctor’s instructions standardized diagnosis and treatment.