Knuckle pads (syn. Garrod’s pads; holoderma)

Knuckle pads are common circumscribed thickenings overlying the finger joints. Most lesions occur over the proximal interphalangeal rather than the metacarpophalangeal joints. Knuckle pads are classified as a form of fibromatosis along with Dupuytren's contracture (palmar fibromatosis).

This chapter is set out as follows: 

• Most knuckle pads are idiopathic or related to repetitive trauma, the latter are sometimes referred to as pseudo knuckle pads 
• There is a strong association with other fibromatoses such as palmar fibromatosis (Dupuytren's contracture)
• Some cases of knuckle pads are familial and may be part of a syndrome, eg, the Bart-Pumphrey syndrome (BPS), which is an autosomal-dominant disorder characterised by hearing loss, leukonychia, knuckle pads and palmoplantar keratoderma

• Onset is usually between 15-30 years of age; however, lesions typically develop slowly and asymmetrically and may not present significant cosmetic problems for several years

Distribution

• ​Most lesions occur over the proximal interphalangeal rather than the metacarpophalangeal joints or the distal interphalangeal joints

Morphology

• Well-circumscribed, smooth or scaly, firm, skin-coloured (or sometimes hypopigmented) plaques or nodules

• Knuckle pads caused by trauma tend to regress if the stimulus is removed, other lesions tend to persist 

• Although there is no reliably effective treatment, emollient creams and ointments may be useful if the skin is uncomfortable, and some patients benefit from intralesional steroids. Recurrence and keloidal scarring are common following surgery, and cryosurgery is ineffective