Psoriasis

Psoriasis is chronic skin disease characterized by persistent epidermal hyperplasia. Classically, the patient will present with sharply demarcated, dry, scaling papules and plaques of various sizes, with an edematous, inflamed base, usually on the dorsal surfaces of the trunk and extremities. It can vary from scaly lesions only found on the elbows to a wide-spread skin disorder associated with arthritis (psoriatic arthritis). (Berkow 1992; Park 2005)

The cause of psoriasis is idiopathic, but is frequently familial and has a world-wide distribution. In some patients the first occurrence of the lesions appear with local trauma, sunburn, or after a viral infection. In others the cause appears to be iatrogenic, associated with drugs such as corticosteroids, antimalarial drugs, lithium, aspirin and beta-blockers. Similar to atopic dermatitis, psoriasis has a basis in nervous function, and can be brought on during periods of acute stress — researchers have even isolated increased concentrations of neurotransmitters in psoriatic plaques. Autoimmunity is another potential cause of psoriasis, with the lesions being associated with the increased activity of T cells in underlying skin. Experimental models have shown that psoriasis can be induced by stimulation with streptococcal superantigen, which cross-reacts with dermal collagen, increasing T cell activity. (Berkow 1992; Park 2005)

The onset of psoriasis is typically gradual, and the course of the disease is marked by chronic remissions and acute exacerbations that can vary in frequency and duration. Regions where psoriasis is frequently found include the scalp, the extremities (elbows and knees), sacrum, buttocks and penis, as well as the nails, eyebrows, armpits, umbilicus, and anus. During remission the lesions heal without scarring and hair growth is normal. Nail involvement is frequent and often resembles a fungal infection.

Medical treatment

Medical treatment for psoriasis is essentially very similar as that of atopic dermatitis, with topical corticosteroids being the mainstay of treatment. Topical retinoids such as tazarotene is applied as an aqueous gel to modulate the differentiation and proliferation of epithelial tissue, and is thought to have an antinflammatory and immunomodulatory activity. Vitamin D₃ analogs such as calcipotriene are a new class of topical drugs that are used in patients with resistant lesions, but is more expensive than steroids. Other drugs include immunosuppressive agents such as methotrexate and cyclosporine, but carry with them a significant risk of deleterious side effects. Another therapy that is sometimes used is psoralen ultraviolet A light therapy (PUVA), which may produce remissions lasting several months, but may increase the incidence of ultraviolet-induced skin cancer. The concomitant use of oral retinoids with PUVA has been shown to decrease the dose of ultraviolet light needed to induce remission. (Berkow 1992; Park 2005)

Holistic treatment

In holistic circles there are a variety of perspectives on the cause and treatment of psoriasis. In Western herbal medicine psoriasis is caused by the usual suspects: improper digestion, an increased toxin and immunological burden, and hepatic congestion. At the root of these causes is intestinal permeability syndrome, and thus measures are undertaken to remove dietary items that damage the gut wall, restore integrity to the intestinal mucosa, promote a healthy bowel ecology, and remove the toxic burden through promoting alterative and eliminatory changes. In Ayurvedic medicine the cause of psoriasis relates to the presence of ama trapped in the skin and failure of the blood to metabolize and remove it, whereas in Chinese medicine psoriasis relates to pathogenic factors that include Blood stasis, Dryness, or Heat and Dampness. At its root psoriasis appears to be related to a localized, dysfunctional immune response in the skin that induces cellular proliferation. From a functional medical perspective, the cause of this is some toxin or antigen-antibody complex, or some aspect that causes a derangement in immune function. Underlying all these notions is a fundamental derangement in digestive function, and thus measures should be undertaken to isolate and remove antigenic foods, and otherwise consume a diet that is suitable and healthy for the individual.

In Ayurvedic medicine there is strong link between the complexion and the archetypal nature of the sun: in health the skin is said to display a natural luminescence, just as the sun radiates heat. It is interesting how UV light can actually be used to put psoriasis into remission when we consider this connection. Traditional PUVA therapy consists of using a psoralen (e.g. methoxsalen) in conjunction with UV-A light. Psoralens are also found is the plant kingdom, most notably in Ammi vishnaga and Psoralea coryfolia, and have been used for thousand of years to treat psoriasis in conjunction with sun exposure. In his book The One Earth Herbal Sourcebook (2001) author Alan Tillotson indicates that the Indian herb Katuka (Picrorrhiza kurroa) strengthens the effect of psoralens, and has obtained clinical results using Katuka in combination with Psoralea (4:1 extracts, 2 g twice daily), in conjunction with exposure to sunlight for a minimum of 20 minutes daily (425). Tillotson notes that the best results occur in conjunction with alterative and eliminative therapies outlined under atopic dermatitis following treatment to prevent recurrence. Additional therapies outlined under atopic dermatitis to promote healing, relieve pruritis should also be included.

Useful Ayurvedic formulas for psoriasis include Kaisara Guggulu (2 pills twice daily), taken along with extracts of Neem (Azadirachta indica) and Vakuchi seed (Psoralia corylifolia). In Chinese medicine, useful formulas in psoriasis include Liang Xue Xiao Feng Tang (for Heat-Wind) and Niu Pi Xuan Hao Fang (for Blood Heat and Blood Stasis). Useful heat-reducing herbs include Sheng Di Huang (Rehmannia glutinosa, raw), Huang Qin (Scutellaria baicalensis), Jin Yin Hua (Lonicera japonica), Sheng Shi Gao (Gypsum). Herbs to relieve Wind and dryness: Mai Men Dong (Ophiopogon), Tien Men Dong (Asparagus cochinchinensis) and Bai Shao (Paeonia lactiflora). Herbs to move blood include Dan Shen (Salvia miltiorrhiza) and Dang Gui (Angelica sinensis).