Pachydermodactyly does not need rheumatologic work-up

NK Sinha¹, SP Ling², SK Nema¹, DR Pai³,  
¹ Department of Orthopaedics, MMMC Melaka, Malaysia
² Department of Student, MMMC Melaka, Malaysia
³ Department of Surgery, MMMC Melaka, Malaysia

Correspondence Address:
N K Sinha
Department of Orthopaedics, MMMC Melaka
Malaysia

Full Text

Sir,

Pachydermodactyly (PDD) is a rare type of dermal swelling on the sides of proximal interphalangeal (PIP) joint, typically affecting several fingers of hands in males. If not recognized, it can be misdiagnosed as rheumatologic arthropathy, leading to unnecessary investigations.

A 24-year-old Chinese girl presented with a small pain-less, fusiform, non-progressive soft-tissue swelling on the radial aspect of PIP joint of ring fingers of both hands [Figure 1]. Patient had a compulsive habit of holding her finger at the PIP joint and pulling it to crack it whenever she felt mental distress [Figure 2]. She had been doing this manipulation 4-5 times in succession several times each day since last 12 years. There was no history of trauma or local disease. No other family member had a similar swelling. On examination, it was a diffuse non-fluctuant thickening of the dermis with no definite margin. There were no signs of synovitis, joint line tenderness or joint laxity. Range of movement was normal. No similar swelling was noted in other fingers or toes. X-ray showed a soft-tissue swelling over radial aspect of PIP joint of both ring fingers. The blood investigation was normal. The patient was explained about the diagnosis of PDD and its benign course. She was counseled about the treatment options, which included avoiding mechanical manipulation of the part and intralesional triamcinolone injection. Since, it was asymptomatic, non-progressive and affecting only one side of the ring fingers, she opted for cessation of mechanical manipulation of the PIP joint and follow-up as required.{Figure 1}{Figure 2}

PDD can be diagnosed clinically as a dermal swelling with no symptoms, no pain and a normal joint function. [1],[2],[3] The diagnosis is supported by a normal blood and a radiological finding showing only a soft-tissue swelling. Histopathological investigation shows an increased dermal collection of collagen. [1],[2],[4],[5] However, it is not essential for diagnosis. [1],[2],[3],[4],[5]

Bardazzi proposed a classification, which is widely referred to in the literature. [6] His classification describes 5 types: (1) Classic PDD frequently associated with mechanical trauma, (2) MonoPDD or localized PDD (3) transgrediens PDD with cutaneous thickness extending to metacarpophalangeal region (4) familial PDD, which may be transgradiens and (5) PDD associated with tuberous sclerosis. The differential diagnoses include, knuckle pads, chewing pads, collagenous plaques of the hands, juvenile digital fibromatosis, progressive nodular fibrosis of the skin, foreign body granuloma, thyroid disease, pachydermoperiostosis (Touraine-Solente-Golé syndrome), acromegaly, connective tissue nevi, fibrosing inflammatory conditions, Garrod's pads in violinists, acropachydermodactyly in psoriasis, paraneoplastic acropachydermo-dactyly, rheumatoid nodule, Thiemann's disease, and sarcomas. [2],[4]

PDD is being recognized as one of "factitious disorders" of the upper limb. [3] Psychiatric counseling should be given for patients with obsessive-compulsive behavior. It responds well to intralesional triamcinolone injection. [2],[4] Surgical excision of excessive dermal tissue may be indicated in some cases. "Watchful observation" may be a preferred option in many cases due to their benign course. [2],[4] Cessation of mechanical manipulation can lead to natural regression. [1],[2],[3],[4],[5]

In conclusion, awareness about PDD can lead to an early clinical diagnosis without extensive investigation and initiation of appropriate treatment.

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