21: Mechanical/Biomechanical Skin Lesions - Bennett Flashcards
causes of hyperkeratosis
- Mechanical stresses (improper or poorly fitting shoes) - Abnormal foot mechanics (bony or biomechanical deformities) - High levels of activity
what is a diffuse shearing callus?
- Weight bearing surface of the sole - Usually asymptomatic - Pain if they dry and fissure - Even thickness, undefined margins - Related to abnormal shearing/friction forces - Treatment = control abnormal pronation, tissue debridement, surgery
what is a discrete nucleated callus?
- Usually isolated
- Painful
- Central conical core of keratin at greatest pressure
- Can often be confused with plantar’s wart
- Plantar warts are more sensitive to side-to-side compression, whereas this callus causes pain with directed pressure
porokeratosis plantaris discreta
- 1-3 mm punctate lesion
- Weight bearing aspect of sole
- Direct pressure from plantar surface
- Sweat duct involvement
- Hyperkeratosis of epidermal sweat duct
- No vascular involvement
- Can be as deep as 1.5 cm
treatment for porokeratosis
- Topical keratolytics (urea cream 20%)
- Periodic debridement
- Alcohol sclerosing injections (destroys the sweat duct)
- Surgical excision of the lesions
describe a superficial shearing callus
- Shallow nucleus or no nucleus
- Usually asymptomatic
- Debridement
- Skin lines visible underneath (warts have skin lines around lesion)
describe a superficial fibrous shearing callus
- Clear keratin nucleus with white fibrous base that blends into surrounding callus
- Painful when hypertrophic
- Debridement
describe a fibrous nucleated shearing callus
- Deep nucleus with white fibrous plug
- Clearly differentiated margin
- Enucleation painful
- Must remove plug to get relief
- Treatment = Debridement, Curettement, Bone surgery
common callus affecting the hallux due to unstable hallux during propulsive phase of gait
pinch callus
why have a callus plantar to the first met head ?
- Plantarflexed 1st ray
- Enlarged or multiple sesamoids
why have a callus plantar to second and third met head?
- Hypermobile first ray
- Hallux abducto valgus deformity
- Plantarflexed metatarsal
why have a callus plantar to fourth met?
why have callus plantar to fourth and fifth met heads?
- Hypermobile 5th ray
- Plantarflexed 4th ray
- Supinated foot type
- Cavus (rigid) foot type
why have a callus plantar to the hallux IPJ?
- hallux limitus
- IPJ sesamoid
heloma =
Corn
describe heloma durum
- Dense compacted tissue
- Areas of pressure on toes
- Example – lateral aspect of the 5th toe
- May appear dry or waxy
- Conical
- Tx: periodic debridement, topical keratolytics, fix underlying bone pathology, shoe gear modification, padding
describe a heloma molle
- Soft due to moisture
- In between toes (deep in the web space)
- Can be firm
- Painful
- Increased friction and pressure from adjacent bony prominences
tx: drying the interspace, periodic debridement, pressure relief padding, surgical correction of bone pathology
what is a seed corn?
heloma millare
- Soles (can be nonweight bearing areas)
- Lesions range from 1-3 mm in diameter
- Single or multiple
- Deeply imbedded
- Hyperkeratotic plugs
- dry type lesion in comparison to porokeratosis
describe heloma neurvasculare
- Contains both vascular and nerve elements
- Often confused with plantar’s wart (Verrucoid appearing)
- Painful (more so than just a vascular corn)
- Located at a point of increased pressure/pinching of the skin
- Commonly found at the medial hallux, 1st MTPJ, medial heel, or 5th MTPJ.
herniation of enlarged capillaries into the hyperkeratotic lesion
heloma vascularis/vascular corn
- Thin
- Symptomatic
- Plantar weight bearing or at pressure points under the first or fifth metatarsal heads
- Lesions bleed easily with debridement and are slow to heel
tx: silver nitrate, alcohol sclerosing injection, careful not to ulcerate the lesion
