Blisters – Ouch !!!

The Causes- Shear or friction injuries are usually the culprit. Improperly fitting shoes (too tight or too loose), especially when in close proximity to wet, sticky feet can be a problem. For example, long walk offs in your rock shoes without socks can wreck havoc on your feet. That beautiful new pair of hiking boots you bought without breaking in before your epic Pacific Crest Trail adventure may trash your trip. Friction injuries are frequently found over the tops or sides of the toes and at the heel or heel cord.

There can be many causes for blisters in the back country. Other causes in the back country for blisters are sun burn, thermic burns and allergic reactions. Sun burn is usually obvious. Allergic reactions can be from external reactions, such as exposure to poison ivy. The blisters can also be from internal reactions, such as a reaction to medications. External reactions typically occur in exposed areas such as the arms, face and legs where the allergen or sun can come into contact with skin. Internal reactions result in more widespread skin eruptions and frequently involve the abdomen, chest and back. Internal reactions usually occur after taking a new medication. If you suspect an internal allergic reaction this is time for an immediate evacuation.

The Symptoms- Usually pretty obvious. Problems from friction injuries often start out as a red “hot spot” where your boot or clothing may be rubbing against the skin. Things then proceed rapidly to a bubble of fluid under your skin. Allergic reactions usually occur with some delay from contact with the allergen.

The Treatment – Friction injuries: Determine the culprit. If your feet are wet dry them. If you have a friction points try to protect it and make sure there is not something else riding along for the hike in your boot. Change socks to dry ones. Use socks with heels (rather than tube socks). Use technical fabrics such as Coolmax to promote wicking of moisture. Many people recommend a thin line sock liner inside your cushioning sock to minimize the shearing forces.

Red irritation (hotspot) – protect the area with an adhesive bandage such as moleskin. There are a variety of anti-blister products out there so check it out. Simple measures such as medical adhesive tape, band aides or even duck tape can be used. My experience is that the common tapes typically peel off and ball up in your shoe making bad matters worse, so get something that will stay put.

Blister- this is where fluid collects under the skin forming a pocket. If the blister is smaller than the last joint on your little finger you may not wish to drain it. In this case protect it with moleskin with a hole cut out around the blister and then cover with a non adherent dressing such as telfa. You can build up several layers of cut out moleskins to protect the site. If the blister is larger than the last joint on your little finger or is in a problem place consider draining it. Use a sterilized needle (just like your Mom used to) and carefully drain the blister. Try to leave the skin on over the blister. Put a little neosporin over and cover first with a non –adherent dressing such as Telfa. You may use an adherent dressing over and around the non –adherent dressing to keep it in place. If the blister has popped and the skin has come off treat it like an open wound. Place some Neosporin ointment over it and cover again with a non-adherent dressing. Keep it clean.

External Reactions (Sun burn or poison ivy) – Superficial over the counter ointments containing an anti – histamine are good (diphenhydramine or Benadryl). You may supplement these topicals with oral anti-histamine (Benadryl or Diphenhydramine) as well as an anti- inflammatory (Motrin, Naprosyn). Read package directions for dosing instructions.

Internal Reactions- You can give oral anti-histamines but let this delay immediate evacuation to a hospital or doctor for further evaluation.

When to worry- See internal reaction. Other causes for concern:

•   Milky or pus-like fluid in the blister when you drain it. The blister fluid should be clear as spring water. This would indicate a probable infection.
•   Redness around the blister or red streaks extending toward the heart from the blister. Healing wounds usually have some redness around the edges of the wound. However if this is spreading or streaking it probably means there is an infection.
•   Blisters from thermal (heat) burns other than sunburn-thermic burns require extra vigilance in the back country and are treated differently than friction injury, sunburn or allergic reactions. Even second degree burns in the right places can be extremely dangerous. Please stay tuned for future installations on thermic injuries.