Psoriasis is a chronic skin condition where an overactive immune response causes skin cells to build up rapidly, resulting in thick, scaly, inflamed patches called plaques. Applying a covering, known as occlusion, over these plaques after applying a topical treatment enhances the therapeutic effect. This practice is often performed overnight, allowing for maximum contact and penetration of the applied product. This article explores how covering psoriatic plaques works, the safety concerns involved, and the proper technique for application.
How Nighttime Occlusion Enhances Treatment Effectiveness
The primary benefit of covering psoriatic plaques is the physical barrier that addresses moisture loss. Psoriatic skin has a compromised barrier function, and occlusion prevents trans-epidermal water loss, effectively rehydrating the thick, dry plaques. This softening process helps loosen and reduce the characteristic scaling, making the skin more receptive to medications applied underneath.
Occlusion also significantly increases the amount of topical medication that penetrates the skin layers. By trapping the product against the skin, the covering increases the concentration gradient and the duration of contact. This can enhance absorption by up to ten times compared to uncovered application. This mechanism is effective when using thick emollients, which soften the skin, and also applies to medicated ointments.
Enhanced absorption delivers active ingredients, such as corticosteroids or vitamin D analogs, deeper into the affected tissue. For areas with very thick skin, like the palms and soles, occlusion helps overcome the natural barrier posed by the dense stratum corneum. The improved penetration allows the anti-inflammatory and cell-regulating properties of the treatment to work more efficiently, leading to faster flattening and clearing of the plaques.
Essential Safety Warnings and Contraindications
While occlusion is effective, it must be approached with caution due to several risks, especially when combined with potent medications. Covering the skin creates a warm, moist environment that is highly conducive to the growth of bacteria and fungi. Individuals with psoriasis already have a heightened risk of skin infections, and occlusion can promote issues like folliculitis or yeast infections if the skin is not properly cleaned before application.
The most serious warning involves using topical corticosteroids under occlusion, which drastically increases the steroid’s potency. Enhanced absorption of strong topical steroids can lead to severe local side effects, including skin thinning (atrophy), stretch marks, or easy bruising. In rare cases, when very potent steroids are covered over large body areas, enough medication can be absorbed to cause systemic side effects.
Strong corticosteroids should never be covered unless explicitly instructed and supervised by a healthcare provider. Covering areas with thinner skin, such as the face, groin, or skin folds, is contraindicated because the risk of adverse effects is much higher. Any signs of increased warmth, pain, oozing, or yellow crusting should prompt immediate removal of the covering and medical consultation.
Practical Guide to Covering Psoriasis at Night
If a healthcare professional has approved occlusion, the process begins with proper skin preparation. The best time to apply the treatment is immediately after a warm shower or bath, after gently patting the skin mostly dry. Applying the product to slightly damp skin helps lock in moisture before the covering is applied.
Apply the prescribed medication or a thick emollient ointment only to the affected plaque area, using a small amount and gently rubbing it in. The goal is to cover the plaque, not to layer on an excessive amount of product. Once the treatment is applied, the area is sealed with an occlusive material to create the barrier.
Common materials include household plastic wrap, cellophane, or specialized waterproof dressings. For plaques on the hands or feet, cotton gloves or socks can be worn over the applied ointment and covered with a plastic bag or disposable vinyl gloves for better occlusion. It is recommended to limit the duration of occlusion to overnight or for a few hours, following specific medical instructions, to give the skin a break and monitor for irritation or infection.