How are botanical dermatoses treated?

Updated: Aug 23, 2019
  • Author: Glen H Crawford, MD; Chief Editor: Dirk M Elston, MD  more...
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Answer

Exposed areas should be washed immediately with copious amounts of water. Soaps should be used only after a thorough washing with water because they may actually expand the area of resin exposure on the skin. If washing is delayed by 10 minutes, only 50% of the urushiol can be removed. By 60 minutes, washing is ineffective. Allergic contact dermatitis is self-limited and typically resolves in 3-4 weeks. Symptom relief is the main therapeutic goal. [28]

After vesicles appear, weepy and/or crusted areas may be treated with wet-to-dry soaks of aluminum acetate. Superpotent topical corticosteroids may be beneficial if applied before vesicles appear. Systemic steroids (eg, prednisone) are extremely effective when indicated and are best given in a dose of 1-2 mg/kg/d. The dose should be slowly tapered over 2-3 weeks; otherwise, relapse occurs. Alternatively, treatment with intramuscular triamcinolone acetonide 1 mg/kg yields the same effects; typically, this drug has fewer adverse effects related to increased appetite and water retention. Methylprednisolone dose-packs are frequently associated with rebound flares of dermatitis because they deliver a lower dose of steroid for only a short course.

Oral antihistamines are not effective, and topical antihistamines can complicate matters by inducing an allergic reaction on dermatitic skin. To date, oral hyposensitization programs have failed. Most patients develop pruritus ani, generalized pruritus, and urticaria; they commonly report that the treatment is worse than the condition.

More than 150 different barrier creams have been tested. In 1995, Marks and coworkers published encouraging results with an organoclay compound, 5% quaternium-18 bentonite lotion (IvyBlock; EnviroDerm Pharmaceuticals, Louisville, Ky), which is available as an over-the-counter preparation. [29]

For centuries, the herbal remedy jewelweed (Impatiens species) has been used to treat poison ivy exposure. A randomized, double-blinded, paired comparison demonstrated that jewelweed is not effective in the treatment of allergic contact dermatitis due to poison ivy. [30]

In the case of widespread and severe Asteraceae-induced dermatitis, potent topical steroids and oral prednisone are relatively ineffective unless they are used early. Azathioprine may help in protracted cases (eg, chronic photosensitivity dermatoses). Dosing is based on functional levels of the enzyme thiopurine methyltransferase. Chloroquine, ethinyl estradiol, and psoralen UVA (PUVA) with or without prednisone have been reported as helpful in some cases. [31] Whole body mechlorethamine may be temporarily effective. Cyclosporin often results in severe rebound upon its discontinuation and should be avoided.


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