Thorns and blisters: unexpected summer holiday hazards

Warm weather tempts us to wear sandals or even go barefoot. This increases the risk of exposing part of your foot to injury, such as thorns and blisters. How you deal with the injury if you have diabetes could be the difference between ending up with a successful outcome and having to seek emergency care because the situation has complicated.

Many people are all too quick to self-diagnose and self-prescribe treatment, especially with thorns and blisters. The media and the internet constantly bombard us with information and a variety of products in convincing campaigns. Packaging instructions often leave much to be desired – since warnings for people with diabetes or peripheral vascular disease are often in tiny-sized type, unable to be read by people with less than perfect vision.

Annual diabetic foot assessment

Before summer arrives, if you haven’t already done so this year, make an appointment to visit your podiatrist to have your annual diabetic foot assessment done.

The thorough assessment should cover musculoskeletal examination of your joint function, flexibility, range of motion, and loss of shape/bony protuberances. It should also assess your skin texture, hydration/lack of hydration, presence of infection in skin or nails, presence of callus or corns indicating high-pressure areas.

The podiatrist will also carry out a comprehensive vascular examination of your feet to establish whether you have good blood flow. The assessment also includes a full neurological sensory exam to pick up any warning signs of loss of sensation (neuropathy). These measurements are tiny yet vital to knowing what risk your feet may be at. Feet are classified into risk categories after an assessment.

Risk categories

LOW-RISK classification is given to those people living with diabetes who have no risk factors. For example, there is no loss of sensation, no sign of peripheral vascular disease, no history of foot ulceration (breaks in the skin that are difficult to heal), no foot deformity, no foot infections, no high-pressure areas, and normal vision.

People with diabetes in the low-risk classification have low chances of developing foot complications and foot ulcers. They may not need regular podiatry treatment since their feet are in good condition. They must, however, have an annual full screening to compare year to year.

MODERATE-RISK people with diabetes are those with one risk factor (neuropathy,
or peripheral arterial disease, or foot deformity) and no previous history of foot ulcer/amputation. Risk factors are:

  • Loss of feeling/altered feeling in their feet.
  • Reduced circulation in the feet.
  • Hard thick skin, corns or callus on the feet.
  • Vision has been affected.
  • Shape of foot is altered/there are bony protuberances present.
  • Signs of redness on the feet after taking off shoes.
  • Person who cannot look after their feet themselves.
  • Infections present on the skin or in the toenails.

HIGH-RISK people with diabetes have two or more risk factors (neuropathy, peripheral arterial disease, or foot deformity) and/or a previous history of foot ulcer/ amputation. High risk factors to develop foot ulceration are:

  • Loss of feeling/altered feeling in the feet.
  • Reduced circulation in the feet (verified by Doppler or ABPI test).
  • Hard thick skin, corns or callus.
  • Vision impairment.
  • Shape of foot is altered/there are bony protuberances.
  • Signs of redness on feet after taking off shoes.
  • You are unable to take care of your own feet.
  • Infections on the skin or in the toenails.
  • Previous ulceration.
  • Previous amputation.
  • On renal dialysis treatment.

Actions to take

If your feet are moderate or high-risk, you should:

  • Wear protective versions of footwear and skip the strappy sandals that can expose you to harm.
  • Use a SPF30 sunblock on exposed areas of ankle or feet to prevent sunburn.
  • Wear flip flops to protect the soles of your feet from hidden germs and fungi in public showers or swimming pool areas.
  • All injuries to the foot in a moderate- or high-risk foot should be reported to your podiatrist or doctor.
  • Products and actions that are perfectly fine on non-diabetic feet (that have good working pain sensation and good blood supply) can be dangerous if used on moderate-risk or high-risk diabetic feet with nerve damage (neuropathy), or a combination of nerve damage and poor blood circulation (neuroischaemia). It may not be that the product itself is ‘bad’ but the fact that it may cause a problem if used in the wrong way. It may also mask a problem in a foot with less than perfect sensation, or prevent you from getting professional care.

Always carry an emergency kit

Whether you’re going to the beach, or if you’re going to be away on holiday at a location that is far from medical assistance, be sure to pack a basic emergency kit. This should consist of a pair of scissors; a fine tweezer; a sewing needle and a flick lighter to sterilise it; a small bottle of a liquid disinfectant soap, such as Bioscrub or Savlon; a small bottle of surgical spirits or surgical alcohol; cotton wool; a pack of gauze; a tube of disinfectant cream, such as Betadine or Germolene; plasters; a miniature magnifying glass; and two crepe bandages plus two safety pins. Always carry a spare bottle of water. All these items are available from a pharmacy.

How to get a thorn out of your foot

Please note: this should only be done if you are far from medical assistance.

  1. Do not put your weight on the affected foot as it may drive the thorn/splinter/prickle deeper.
  2. Before you start trying to get the thorn out, it is a good idea to wash your hands and the area of the injured area with soapy water. Then pat dry with a square of gauze.
  3. Use the tweezer to grab the end of the thorn and pull out slowly and gently. Pull in the same line of entry that the thorn went in otherwise you risk breaking it if you pull against it.
  4. If this doesn’t work, sterilise the pointy end of the sewing needle for a few seconds with the end of the flame from the lighter. Wait a second or two for the needle to cool down, then gently push against the end of the thorn and work it back out enough to use the tweezer to pull it out.
  5. If this doesn’t work, soak a wad of cotton wool with the disinfectant and water and hold it up against the part of the foot with the thorn in it for at least 3 minutes so that it can soak and soften the skin. Then try again to loosen the skin around the end of it so that it can be pulled out.
  6. If this doesn’t work, apply antiseptic cream and a plaster to cover it so it doesn’t catch on anything until such a time as you can get to medical help.
  7. Thorns and prickles can be difficult to get out, and are more likely to become infected.

DO NOT: squeeze a thorn. This makes it more likely to split apart and break, increasing risk of infection.

NB! If you have moderate- or high-risk feet, do not attempt to remove the thorn without a trained medical person. Loss of protective sensation will mean that you won’t feel pain while probing for the thorn and you may inadvertently cause more harm.

When to seek medical help urgently

You should definitely seek medical help if the thorn/splinter is under your toenail and you can’t get it out, and if the area is red, oozing, swelling or warm to the touch as this may indicate an infection and medical extraction and care is needed.


Slivers of glass can usually be taken out fairly easily. Staining the skin with Betadine liquid can highlight a hidden piece of glass since the glass will show up clear against the stained skin background.

How to treat a blister

Blisters develop because of friction or rubbing, warmth and moisture, such as sweat. You should plan on changing socks during the day if you know that your feet will sweat. Always ensure you have the correct fit of shoes or sandals. Remember, feet normally swell by as much as 7% within 4 hours of getting up in the morning.

Small blister

If a blister is smaller than a 10c coin, wash the overlying skin gently with disinfectant, gently pat dry and apply a plaster to cover and protect it. The blister should re-absorb once the cause of friction has been removed and you are wearing sufficient protective padding.

Large blister

If the blister is larger than a 10c coin, it is more prone to split open and become infected so you should release the pressure in a controlled, sterile way. See below:

  1. Pour surgical spirits over the blister to disinfect the overlying skin.
  2. Disinfect the pointy tip of a sewing needle by passing it under the end of a flame for a few seconds.
  3. Then gently puncture the edge of the blister. Never puncture the centre of the blister.
  4. Mop up the blister liquid with cotton wool and disinfectant.
  5. Using a fresh piece of gauze moistened with disinfectant, gently press down on the top of the blister to release all the blister liquid.
  6. Pat dry with more gauze and cover with an adhesive plaster.
  7. Avoid submersing the blister site in water for the next 4 days but change the dressing daily and keep the rest of the foot clean. The roof of the blister will act as a protective layer while the new skin repairs itself underneath.

Keep the area dry, padded and protected until complete healing takes place.


Anette Thompson
Anette Thompson (M Tech Podiatry (UJ) B Tech Podiatry (SA)) is the clinical director at Anette Thompson & Associates, Incorporated, a multi podiatrist practice in KwaZulu-Natal. Tel: 031 201 9907. They run a member service for Diabetes SA members at their Musgrave consulting rooms as a service to the community.