Common Foot Disorder Flashcards
Describe the pathophysiology of corns and calluses
Normally, the rate of mitotic division in basal cell layer is the same as the rate of surface cellular desquamination (complete replacement is 1 month)
During corn or callus development, friction and pressure increase mitotic activity of the basal cell layer, leading to the migration of maturing cells through the prickle cell and granular skin layers. This results in hyperkeratosis
What factors contribute to corns and calluses?
Friction due to loos or tight fitting shoes
Structural biomechanical problems
Not wearing socks with shoes or wearing ill fitting socks
Walking barefoot
Weight gain
Secondary condition (plantar warts)
What is a corn?
Clavus
Small raised, sharply demarcated, hyperkeratotic lesion
Central core/cone (radix) which is triangular shaped and points inward (hard corns)
Soft (heloma molle), hard (heloma durum) or plantar
What are the signs and symptoms of a hard corn?
Well defined
Yellowish-grey colour
Few mm to 1 cm or more in diameter
Shiny, dry and polished with a loss of normal skin pattern
Central core visible
Pain
Affects skin directly overlying bony prominence or may occur on soles of feet
Usually occurs on the surface of the fourth or fifth toes
What are the signs and symptoms of a soft corn?
Whitish thickening of skin Soft in appearance Usually found on webs between fourth and fifth toes May be painful Often confused with athlete's foot
What is a plantar corn?
A corn on the plantar surface of the foot that causes pain on ambulation
May be confused with a plantar wart
What is a callus?
Callosity or tyloma
Superficial patches of hornified epidermis
No central core
What are the signs and symptoms of a callus?
Yellow-white Normal skin patter, no central core Borders are not well defined Few mm to several cm in diameter Slightly elevated Found on areas where the upper layers of skin are naturally thick (i.e., soles of feet, especially on the heel or ball of the foot)
Describe the pathophysiology of a plantar wart
HPV enters the skin through small cut or abrasion
It infects the upper epidermis and causes squamous epithelial cells to proliferate
It can remain latent or cause subclinical infection (there’s an infection but it can’t be seen)
What is a plantar wart?
Common viral infection of the skin and mucous membrane
Benign tumour caused by HPV
Incubation period is between initial infection to warty lesion varies between 1 and 8 months
Warts are not permanent (they spontaneously clear between 6 months and 5 years)
If plantar warts spontaneously clear, why is it important to treat them?
They can spread
They are unsightly
They can be painful and restrict activities
They have the potential to transform into malignant lesions
What are the signs and symptoms of plantar warts?
They can occur on the sole of the foot, sole of the heel, great toe, head of metatarsal bone and ball
They are circular lesion with wart in the centre
The surface is rough, greyish-brown and friable surrounded by skin that is thick and heaped
Normal patter of skin is interrupted
Thrombosed capillaries appear as black dots in the centre of the lesion or as pin point bleeding sometimes described as seeds
Singly or in clusters
Usually painless unless direct pressure is applied
When completing differential diagnosis of common foot disorders, what other conditions should be considered?
Hard corn: callus, plantar wart
Soft corn: tinea pedis
Callus: corn, plantar wart
Wart: callus, corn, squamous cell carcinoma
What are the goals of therapy for corns and calluses?
To remove the corns and calluses
To avoid and prevent complications
To prevent recurrence
What are pharmacological treatment options for corns and calluses?
Salicylic acid is the first line treatment
For self treatment use: plaster vehicle (12-40%), collodion vehicle (12-17.6%)
Compare SA dosage forms used to treat corns and calluses
SA collodion: proxylin and various volatile solvents, such as ether, acetone and alcohol or a plasticizer (castor oil. Concentration: 17-17.6%
SA plasters/disk/pads: a uniform or semisolid adhesive mixture of SA in a suitable base which is spread on appropriate back material. Concentration: 40%
What are the advantages of SA collodion?
Forms film which prevents moisture loss
Usually easiest to apply for patent
Less apt to run onto other areas of skin
What are the disadvantages of SA collodion?
Takes longer to resolve
Flammable and volatile
Occlusive nature allows systemic absorption of drug
More irritating than other formulations
What are the advantages of SA plasters/disks/pads?
Provides direct and prolonged contact with skin
Plasters may be cut to fit size of lesion
Disks or pads are more convenient
Easy to apply
What are the disadvantages of SA plasters/disks/pads?
Patient may be sensitive to adhesive
When should collodions be used? What’s the duration of treatment?
More useful in the treatment of soft corns rather than calluses
Hard corns and calluses: up to 14 days or earlier
Soft corns: 3-6 days
For what should plasters, disks and pads be used? For who long?
Hard corns and calluses are most easily treated with plasters
Maximum of 5 treatments over a 2 week period
1 treatment is a maximum of 48 hours at a time
How are collodions used?
Soak foot for 5 minutes, dry foot and apply once or twice daily
Apply 1 drop at a time until area is well covered
Allows drops to dry and harden
Do not let adjacent areas of skin come in contact with drug
Periodically soak foot in warm water and remove macerated skin
