Information about the use of occlusion in the treatment of psoriasis.

The verb “occlude,” as it typically applies to psoriasis, means simply “to cover up.” Using medications “under occlusion” means that a topical drug has been applied to the skin, and then covered. This covering (Saran Wrap or clingfilm, latex gloves, bandages, what-have-you) prevents medications from evaporating, or accidentally being rubbed or washed off, thus keeping them at the site of treatment. Using medication under occlusion, therefore, increases the potency of the medications many-fold. However, and it is vital to remember this, it also increases the risk of side effects by the same amount.

Drugs most often used under occlusion include topical steroids and coal tar, but almost anything you can put on your skin can be occluded. One notable exception is Dovonex, which shouldn’t be occluded because of the probablility of skin irritation (Dovonex shouldn’t even be used in “skin fold” areas such as the armpit or groin — so-called “natural” occlusion).

Because of the increased potency of drugs under occlusion, and the increased risk of side effects, you should only use occlusion of drugs under the supervision of a qualified dermatologist who has experience with this practice. I cannot emphasize this enough. Beyond the increased risk of side effects from the drugs, an occlusive dressing typically makes the skin warmer and more moist, increasing the odds of it becoming a nice breeding ground for bacteria or fungi.

Even non-medicated substances such as moisturizers will be more “potent” if used under occlusion. If psoriasis or any other skin condition is giving you cracked skin on your hands, for example, moisturizing and then covering them with surgical gloves (perhaps while you sleep) can be a big help. Bread bags or the like could be used for occlusion of the feet, but be extremely careful as doing something like this can turn walking into slipping.

Since most occlusive materials act as a moisture barrier, occlusion also prevents the skin from doing its job as a heat regulator. Wrapping your entire body in plastic film could drive your temperature up, leading to the possibility of passing out.

Occlusion by itself, without moisturizers or medication, can also lead to improvement in psoriasis. Just wrapping an area in a bandage, or taping it, can bring some improvement, but it tends to take a while. The mechanism through which this works is not really known, but I’ll speculate it’s at least partly due to the increased moisture and partly due to the increased warmth.

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