Poison Oak and Treatments

A few months ago after a 100 mile bike ride I had poison oak rash for the first time in my life. I've brushed into a plant either on the bike or on my 'brick' trail run. Luckily it was just a few blisters and it helped to just get me acquainted with this scourge. Two weeks ago I got another reintroduction, this time it was a pretty bad rash at too many places. I've never treated poison oak before so this was another good exercise of patience and skill.

If I had at least known I had touched poison oak or ivy, I might have limited the spread. I never quite figured out how and when I got it, so I didn't do any of the immediate steps below. (My wildest theory - from handling my tomato plants that keep getting eaten by dears.  Dears might be carrying plenty of urushiol from poison ivy or oak on their fur).

Poison Oak Treatment Plan:

1. Remove as soon as possible as much allergen as possible before rash
   - Use cold water right away to wash off and close pores to reduce skin penetration  (within first two hours)
   - Use alcohol pads to remove some more oil and dry out skin
   + Do not put on the same clothes without washing.
   
   Obviously you need to see a doctor if the rash is systemic and not just on skin!
   
2. Otherwise home treatment of rash is patience and
   - Either try to leave it alone and bear it for the next 2 weeks.  Try meditation ;)
   + Hot water treatment helps - itching is all but unbearable at first,
   keep under hot water until it feels better, and then you are out of histamine for 4-6 hours of relief
   + Drugs: antihistamines, take orally to control dosage.
    I am comfortable with alternating hot water and Diphenhydramine (Benadryl):
      Start just at night for first 3 days, and then twice daily 1x25mg.  See more below.
   - Avoid sprays and creams - it is too easy to overdo antihistamines
   - Avoid hydrocortisone - in a cream it was almost ineffective, worse keeps the skin moist
   - Maybe try calamine lotion - soothing and drying effects should help, especially if blisters are bad.
        Calamine worked well when I got chicken pox (at 25!), but I didn't try it this time.

Antihistamines, Pros and Cons

Overall, for poison oak, I'll stick to Diphenhydramine. Mainly since Diphenhydramine is an old, well tested antihistamine and has no known long term use side effects.  I still don't like drugs affecting the central nervous sytem and Diphenhydramine readily crosses the blood-brain barrier.  Potential drowsiness and concentration impact makes its use best left for just before going to bed or midday in the office ;)  Good news that after 3 days tolerance against its sedation effects is built up[1]

Cetirizine (Zyrtec) might be a better newer choice for other longer period antihistamine needs as it is less drowsy, single daily dose.  Some other antihistamines don't mix well with some antibiotics.

   * DUI potential.  Blood levels would be minimal at the standard Diphenhydramine dose, but definitely
   + Don't mix with alcohol!

   * Import restrictions.  Good to keep in mind it is strictly prescription in Russia as an opiate base, and banned in Zambia.  In my travel medkit I have some Diphen, and I didn't even think about it for the trip to Singapore and Indonesia.
  + Hopefully just a few tablets will not get me in trouble.  Don't keep much of this on you or at home.

   * Overdose: Finally and very sadly, an MIT friend succeeded at committing suicide with Benadryl.
     Please talk to somebody, even if you intent to just ask how much it takes. Hopefully, you will find many reasons to live instead!