21 - Mechanical and Biomechanical Skin Lesions Flashcards
What to focus on
- **Recognize the characteristics associated with each of the lesions **
- Know the specifics and any distinguishing features
Mechanical lesions of the foot
- Hyperkeratosis
- Forms of calluses
- Callus location and types
- Classification of helomas
Hyperkeratosis
- Thickening of the skin
- Stimulation of the epidermis by increased or chronic pressure or friction
- Increased keratinocyte activity
- Normal protective response
Causes of hyperkeratosis
- Mechanical stresses (improper or poorly fitting shoes)
- Abnormal foot mechanics (bony or biomechanical deformities)
- High levels of activity
Two types of calluses
o Diffuse shearing callus
o Discrete-nucleated callus
Diffuse shearing calluses
- Usually a flat lesion, but you really need to palpate the callus to determine the thickness of the callus and the skin around it
- Weight bearing surface of the sole
- Usually asymptomatic – typically NO pain
- Pain can occur if they dry and fissure
- Even thickness, undefined margins
- Related to abnormal shearing/friction forces
Treatment for diffuse shearing calluses
- control abnormal pronation
- tissue debridement
- surgery
Discrete nucleated calluses
- Usually isolated and PAINFUL
- Central conical core of keratin at greatest pressure – not just flat, there is a CORE associated with it!
- Can often be confused with plantar wart
- Plantar warts are more sensitive to side-to-side compression, whereas this callus causes pain with directed pressure
Treatment for discrete nucleated calluses
- Controlling abnormal pressures
- Cushioned inserts
- Prescription orthotics with an accommodative area
- Periodic local tissue debridement with protective padding to reduce pain
- Surgical correction of underlying bone pathology
Example of surgical correction
- Example: plantarflexed metatarsal head or osteophyte/bone spur
- Can relieve pain by surgically fixing the biomechanical/osseous deformity
- NOTES: might want to be a little more aggressive with the treatment of this, because they will be in pain and you will be able to give them relief by debriding – some of these can be very deep
Classification of calluses
- Porokeratosis plantaris discreta
- Superficial shearing callus
- Superficial fibrous shearing callus
- Fibrous nucleated shearing callus
- Pinch callus
Porokeratosis plantaris discrete
- **NOTE: ALWAYS ASSOCIATED WITH A SWEAT DUCT **
- 1-3 mm punctate lesion
- Weight bearing aspect of sole
- Direct pressure from plantar surface
- Sweat duct involvement (can see moisture during debridement)
- Hyperkeratosis of epidermal sweat duct
- No vascular involvement
- Can be as deep as 1.5 cm
Treatment of porokeratosis plantaris discrete
- Topical keratolytics (20% urea cream will suffice - might not get rid of the lesion completely, but it will help to maintain it so they don’t have to come back to get it down as often)
- Periodic debridement
- Alcohol sclerosing injections – completely destroys the sweat duct
- Surgical excision of the lesions – scar formation will be minimal, so it may not be any significant downfall of surgical excision (can be as deep as 1.5 cm, which is very deep, so you will need to use a 64 blade which is rounded to scoop out the lesion)
Superficial fibrous shearing callus
- Clear keratin nucleus with white fibrous base that blends into surrounding callus
- Painful when hypertrophic
- Debridement
Fibrous nucleated shearing callus
- Deep nucleus with white fibrous plug – may have a flat callus, but in the central portion, there will be a nucleus associated with it
- Clearly differentiated margin
- Enucleation painful
- Must remove plug to get relief
Treatment of fibrous nucleated shearing callus
o Debridement
o Curettement
o Bone surgery (for underlying etiology if there is a bony prominence)
Pinch callus
- Common
- Affects hallux
- Unstable hallux during propulsive phase of gait
- Mechanical pathology
Callus locations
GENERAL: calluses are typically on the PLANTAR aspect of the foot
o Plantar to 1st metatarsal head
o Plantar to 2nd and 3rd metatarsal heads
o Plantar to 4th metatarsal head
o Plantar to 4th and 5th metatarsal heads
o Plantar to hallux IPJ
What causes a callus located plantar to first metatarsal head
- Plantarflexed 1st ray
- Enlarged or multiple sesamoids
What causes a callus located plantar to second and third metatarsal head
- Hypermobile first ray
- Hallux abducto valgus deformity
- Plantarflexed metatarsal
What causes a callus located plantar to fourth metatarsal
- Hypermobile 5th ray
- Plantarflexed 4th ray
What causes a callus located plantar to fourth and fifth metatarsal heads
- Supinated foot type
- Cavus (rigid) foot type
What causes a callus located on the plantar aspect of the hallux under IPJ
Hallux limitus (lack of motion in first MPJ, more motion will occur at IPJ))
***IPJ sesamoid (more common)
o A lot of times when we see these, they are significant in diabetic patients
o Can develop into an ulceration
o If you see an ulcer here, you need to take an x-ray to see if they have an IPJ sesamoid
Where are helomas typically locaated?
Helomas (corns)
- GENERALLY ON DORSUM OF THE FOOT
Types of helomas
o Heloma durum (hard corn) o Heloma molle (soft corn) o Heloma millare (seed corn) o Heloma neurofibrosum (neurovascular corn) o Heloma vasculare (vascular corn)
Heloma durum
- Dense compacted tissue
- Areas of pressure on toes
- *****MOST COMMON LOCATION: 5th digit
- Example – lateral aspect of the 5th toe
- May appear dry or waxy
- Conical
Treatment for heloma durum
- Periodic debridement
- Topical keratolytics
- Sclerosing injections
- Resection of underlying bone pathology – contracted toe
- Tendotomy if it is flexible, osseous if it is rigid
- SHOE GEAR MODIFICATION – this will decrease formation
- If you are adding padding to the foot, you NEED to make sure they are also changing their shoe gear or there will be increased pressure and therefore
Heloma molle
Soft corn
- Soft due to moisture
- In between toes (deep in the web space)
- Can be firm
- Painful
- Increased friction and pressure from adjacent bony prominences
Treatment for heloma molle
- Drying the interspace
- Periodic debridement
- Pressure relief padding
- Surgical correction of bone pathology
Heloma millare
Seed corn
- Seed corn
- Soles (can be nonweight bearing areas)
- Lesions range from 1-3 mm in diameter
- Single or multiple
- Deeply imbedded
- Hyperkeratotic plugs
Etiology of heloma millare (seed corn)
- Irritation from footwear
- Anhidrosis – more of a DRY lesion
- Excessive dryness
- Invagination of skin with hyperkeratotic plugs
Treatment for heloma millare
- Involves rehydration of skin
- Topical emollients
- Curettage/sharp dissection of symptomatic lesions
Heloma neurovasculare
- Contains both vascular and nerve elements
- Often confused with plantar wart
Clinical appearance of a neurovascular corn
- Verrucoid appearing
- Painful
- Located at a point of increased pressure/pinching of the skin
- Commonly found at the medial hallux, 1st MTPJ, medial heel, or 5th MTPJ.
Treatment for neurovascular corn
- Debridement with silver nitrate application
- Protective padding
- Alcohol sclerosing injection (reduce size and symptoms)
- Typically utilized for destroying nerves for a nerve problem
- Very conservative way of destroying the nerve compared to surgery
Heloma vascularis
Vascular corn
- Herniation of enlarged capillaries into the hyperkeratotic lesion
- Thin, symptomatic lesions
- Plantar weight bearing or at pressure points under the first or fifth metatarsal heads
- Lesions bleed easily with debridement and are slow to heel
Treatment for vascular corn
- Application of silver nitrate
- Alcohol sclerosing injection
- Careful not to ulcerate the lesion
- These will destroy blood supply to the area
STUDY - Outpatient Care and Morbidity Reduction in Diabetic Foot Ulcers Associated with Chronic Pressure Callus
- Young et al. demonstrated that debridement of hyperkeratotic lesions, or calluses caused by repetitive pressure, reduced peak plantar pressures by 26%
- Sage looked at 233 cases of diabetic foot ulceration preceded by minor trauma, 82.4% (192/233) were preceded by focal pressure keratosis
- Determined that frequent clinical visits were associated with less severe ulcers
- Clearly identified intractable plantar keratosis, heloma durum, pinch callus, and heloma molle as common sources of micro trauma leading to ulceration
- Patients with these conditions with regular office visits for debridement were less likely to ulcerate, require hospitalization, or undergo surgery
- Podiatric office visit $60, if a patient went monthly $720/year compared with a cost of about $25,000 for lower extremity amputation (2001)
NOTE
- Insurance has stopped reimbursing very much for callus removal
- NEED to realize that it is still important to remove the callus for your patient
- Treating and removing calluses will PREVENT ULCERATION OF THE CALLUS SITE***
