Pachydermodactyly

Pachydermodactyly is defined by gradual, asymptomatic thickening of the periarticular skin and soft tissue swelling, mainly affecting the lateral sides of the fingers' proximal interphalangeal (PIP) joints.^[2][3] The most commonly affected fingers are the second, third, and fourth; however, the dorsum of the hand and the fifth finger may also be affected.^[4] Although moderate erythema, fine desquamation, or lichenification may occasionally be seen, epidermal alterations are not typically present.^[5] There is no impact on hand movements.^[6]

Although the specific cause and etiology are yet unknown, excessive mechanical manipulation of PIP joints is likely to be a contributing factor.^[7] The basis for this suggestion is the discovery that pachydermodactyly is related to a variety of jobs and pursuits, including weightlifting,^[6] employment in food processing facilities,^[8] martial arts, climbing,^[9] and individuals with OCD who have hand tics.^[10]

The final diagnosis is clinical and made after ruling out other possible causes of joint swelling. It calls for a high degree of suspicion, especially in individuals who have progressive soft tissue swelling without any pain, soreness, or diminished function.^[11] Unless clinically indicated, laboratory testing such as extractable nuclear antigen test, rheumatoid factor, C-reactive protein, complete blood count, and antinuclear factor are not required.^[12]

A thickening of the dermis, possibly associated with a benign proliferation of fibroblasts, and an increase in collagen fibers that extend to the subcutaneous cellular tissue are the most common histological findings.^[6] In addition, there may be a decrease in mucin and elastic fibers, as well as hyperkeratosis (orthokeratosis or parakeratosis).^[4]

Hand radiographs usually show soft tissue swelling without interphalangeal joint structural involvement.^[13] An X-ray examination shows no abnormalities in the periosteum or bones in pachydermodactyly patients.^[14] Additionally, no changes are seen in the synovium or joints during ultrasound.^[15]

Chen et al. published a diagnostic criterion that consists of six elements: the patient having no symptoms; there being no stiffness in the morning; no restriction on movement; swelling on the lateral aspect of the finger; normal laboratory values; and soft tissue swelling on radiography.^[16]

Differential diagnoses include rheumatoid arthritis, acromegaly, juvenile idiopathic arthritis, pachydermoperiostosis, knuckle pads, and juvenile digital fibromatosis.^[17]

Pachydermodactyly does not currently have a commonly accepted treatment.^[18] Nevertheless, aggressive therapy is usually not necessary due to the disease's benign course.^[19] Since the majority of pachydermodactyly cases appear with symptoms caused by recurrent joint trauma, discontinuing stimulating activities is sufficient to promote regression or stabilization.^[20] It has also been demonstrated that intralesional corticosteroids can sometimes reduce swelling.^{[citation needed]} Intralesional triamcinolone injections have also been reported to alleviate symptoms.^[6] Pachydermodactyly patients frequently have surgery to improve the appearance of a digit.^[21]

• Skin lesion