Exacerbation of psoriasis induced by indomethacin

Brazilian Society of Rheumatology 2020 guidelines for psoriatic arthritis

Psoriatic arthritis (PsA) is a chronic and systemic immune disease characterized by inflammation of peripheral and/or axial joints and entheses in patients with psoriasis (PsO). Extra-articular and extracutaneous manifestations and numerous comorbidities can also be present. These recommendations replace the previous version published in May 2013. A systematic review of the literature retrieved 191 articles that were used to formulate 12 recommendations in response to 12 clinical questions, divided into 4 sections: diagnosis, non-pharmacological treatment, conventional drug therapy and biologic therapy. These guidelines provide evidence-based information on the clinical management for PsA patients. For each recommendation, the level of evidence (highest available), degree of strength (Oxford) and degree of expert agreement (interrater reliability) are reported.

A Review of Drugs that Induce or Exacerbate Psoriasis

Background

Psoriasis is a common disorder of the skin, immune system, and joints that is influenced by genetic and environmental factors. It can be aggravated or induced by drugs.

Objectives

To identify the major drugs implicated in inducing or exacerbating psoriasis and to discuss their characteristics.

Methods

We performed a PubMed literature search for reviews and case reports on drugs that exacerbate or induce psoriasis. Articles were screened by title and abstract and then examined for their findings and references.

Results

Drugs most often reported to exacerbate or induce psoriasis were β-blockers, lithium, synthetic antimalarials, nonsteroidal anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, interferons, tetracyclines, tumor necrosis factor-α inhibitors, and steroid withdrawal.

Conclusions

Characterizing drugs that induce or exacerbate psoriasis by latency and type of psoriatic eruption can help guide clinical reasoning. Although a relatively uncommon occurrence, psoriatic lesions can be caused by drugs, allowing astute physicians to recognize and change their management plans accordingly.

Effectiveness of chondroitin sulphate in patients with concomitant knee osteoarthritis and psoriasis: a randomized, double-blind, placebo-controlled study

OBJECTIVE

The aim of the trial was to assess the efficacy of chondroitin sulphate (CS) on symptomatic knee osteoarthritis (OA) associated to psoriasis.

METHODS

In this randomized, double-blind, placebo (PBO)-controlled clinical trial 129 patients with symptomatic knee OA and concomitant psoriasis were randomized into two groups receiving 800 mg daily of CS or PBO for 3 months. The primary efficacy outcome for knee OA was the Huskisson's visual analogue scale (VAS) and for psoriasis was the Psoriasis Area and Severity Index (PASI). Additionally, other secondary efficacy criteria for both conditions were assessed.

RESULTS

After 3 months of treatment, CS was more effective than PBO, relieving pain VAS (CS -26.9+/-24.8 vs PBO -14.23+/-20.8mm, P<0.01), decreasing the Lequesne index (CS -4.8+/-3.4 vs PBO -3.3+/-3.5, P<0.05) and reducing the number of patients using acetaminophen as rescue medication (CS 43% vs PBO 64%, P<0.05). Regarding PASI, Overall Lesion Severity Scale and Physician's Global Assessment of Change no statistically significant changes were detected in front of PBO. However, CS improved plantar psoriasis compared to PBO (CS 87% vs PBO 27%, P<0.05). Quality of life improved significantly in CS-treated patients according to the Short Form-36 health survey and the Dermatology Life Quality Index (DLQI). CS tolerability was excellent. Adverse events were infrequent and evenly distributed among groups. The incidence of psoriatic flares did not increase after treatments.

CONCLUSIONS

This study confirms the efficacy and safety of CS as a symptomatic slow-acting drug in patients with knee OA and shows that CS improves plantar psoriasis. The use of CS could represent a special benefit in patients with both pathologies since non-steroidal anti-inflammatory drugs have been reported to induce or exacerbate psoriasis.

Resolution of inflammation in murine autoimmune arthritis is disrupted by cyclooxygenase-2 inhibition and restored by prostaglandin E2-mediated lipoxin A4 production

Acute inflammation follows defined phases of induction, inflammation and resolution, and resolution occurs by an active process that requires cyclooxygenase-2 (COX-2) activity. This study aims to address whether this paradigm extends to recognized model of chronic inflammation. We demonstrated that murine collagen-induced arthritis follows a similar sequential course. Interestingly, COX-2 and its metabolite, the presumably proinflammatory PGE(2), are present in the joints during resolution, and blocking COX-2 activity and PGE(2) production within this period perpetuated, instead of attenuated, inflammation. Repletion with PGE(2) analogs restored homeostasis, and this function is mediated by the proresolving lipoxygenase metabolite, lipoxin A(4), a potent stop signal. Thus, the study provided in vivo evidence for a natural, endogenous link between the cyclooxygenase-lipoxygenase pathways and showed that PGE(2) serves as a feedback inhibitor essential for limiting chronic inflammation in autoimmune arthritis. These findings may explain the enigma regarding why COX-2 inhibitors are palliative rather than curative in humans, because blocking resolution may mitigate the benefit of preventing induction.

Anti-Inflammatory Activity of Sertaconazole Nitrate Is Mediated via Activation of a p38–COX-2–PGE2 Pathway

Sertaconazole nitrate is an antifungal agent that exhibits anti-inflammatory activity; however, the mechanism for this action was unknown. We investigated the cellular mechanisms by which sertaconazole exerts its anti-inflammatory activity in keratinocytes and human peripheral blood mononuclear cells (PBMCs). Paradoxically, sertaconazole was found to activate the proinflammatory p38 mitogen-activated protein kinase. Treatment with sertaconazole also resulted in the induction of cyclooxygenase-2 (COX-2) and the subsequent release of prostaglandin E2 (PGE2). Knocking down p38 in keratinocytes using small interfering RNA resulted in an inhibition of sertaconazole-induced PGE2 release confirming that activation of p38 was required for PGE2 production. Additionally, in stimulated keratinocytes and human PBMCs, sertaconazole was found to suppress the release of cytokines. Treatment with anti-PGE2 antiserum or the COX-2 inhibitor NS398 reversed the inhibitory effects of sertaconazole on the release of proinflammatory cytokines, linking endogenous PGE2 with the anti-inflammatory effects. Finally, in an in vivo mouse model of tetradecanoyl phorbol acetate (TPA)-induced dermatitis, the sertaconazole-mediated inhibition of TPA-induced ear edema was reversed by NS398. Biochemical analysis of tissue biopsies revealed increase in PGE2 levels in sertaconazole-treated mice. Thus, activation of the p38-COX-2-PGE2 pathway by agents such as sertaconazole provides anti-inflammatory therapeutic benefits.

Psoriasis in the elderly

Psoriasis is one of the most common chronic skin diseases, and unprecedented increases in the elderly population will make diagnosis and management of geriatric psoriasis increasingly important. Management of psoriasis in the elderly requires consideration of several important factors. Many commonly prescribed drugs can precipitate psoriasis or aggravate pre-existing psoriasis. In addition, elderly patients are at increased risk of adverse drug reactions due to polypharmacy, adverse drug–drug interactions, adverse drug–disease interactions, incorrect use of medication and concomitant comorbidities. Psoriasis is a highly variable disease that requires individualized treatment. The major classes of topical medications include topical corticosteroids, coal tar preparations, calcipotriol, tazarotene and salicylic acid. Phototherapy, including narrowband ultraviolet B, photochemotherapy, psoralen ultraviolet A and excimer laser treatment, can be effective in properly selected patients. Systemic therapy for psoriasis in the elderly should be reserved for severe, extensive cases that have failed to respond to topical treatment, and may include methotrexate, systemic retinoids and immunotherapy.

Drug Exposure and Psoriasis Vulgaris: Case‐Control and Case‐Crossover Studies

Intake of drugs is considered a risk factor for psoriasis. The aim of this study was to investigate the association between drugs and psoriasis. A case-control study including 110 patients who were hospitalized for extensive psoriasis was performed. A control group (n = 515) was defined as patients who had undergone elective surgery. A case-crossover study included 98 patients with psoriasis. Exposure to drugs was assessed during a hazard period (3 months before hospitalization) and compared to a control period in the patient's past. Data on drug sales were extracted by data mining techniques. Multivariate analyses were performed by logistic regression and conditional logistic regression. In the case-control study, psoriasis was associated with benzodiazepines (OR 6.9), organic nitrates (OR 5.0), angiotensin-converting enzyme (ACE) inhibitors (OR 4.0) and non-steroidal anti-inflammatory drugs (NSAIDs) (OR 3.7). In the case-crossover study, psoriasis was associated with ACE inhibitors (OR 9.9), beta-blockers (OR 9.9), dipyrone (OR 4.9) and NSAIDs (OR 2.1). Extensive psoriasis may be associated with intake of ACE inhibitors, NSAIDs or beta-blockers.

Prostaglandin E(2) suppresses CCL27 production through EP2 and EP3 receptors in human keratinocytes

BACKGROUND

The chemokine CCL27 attracts skin-homing T cells. CCL27 production by keratinocytes is enhanced in skin lesions from patients with atopic dermatitis or psoriasis vulgaris. It is suggested that prostaglandin E(2) (PGE(2)) regulates skin inflammation.

OBJECTIVE

We examined the in vitro effects of PGE(2) on CCL27 production in human keratinocytes.

METHODS

Keratinocytes were incubated with TNF-alpha in the presence or absence of PGE(2) . CCL27 secretion and mRNA level were analyzed by means of ELISA and RT-PCR, respectively. Nuclear factor kappaB (NF-kappaB)-dependent transcriptional activity was analyzed by using luciferase assays.

RESULTS

TNF-alpha increased CCL27 secretion and mRNA levels in parallel to NF-kappaB activity in keratinocytes. NF-kappaB p50 or p65 antisense oligonucleotides suppressed TNF-alpha-induced CCL27 production, indicating the requirement of NF-kappaB for CCL27 production. PGE(2) , EP2, or EP3 agonists reduced TNF-alpha-induced CCL27 secretion and mRNA levels in parallel to NF-kappaB activity and CCL2, CCL5, CXCL8, and CXCL10 mRNA levels. Either EP3-specific or dual EP1-EP2 antagonist partially blocked the inhibitory effects of PGE(2) on CCL27 production and NF-kappaB activity, and the addition of both completely abrogated the inhibition, whereas EP1 or EP4 antagonists were ineffective. Intracellular Ca(2+) chelator BAPTA/AM or cyclic adenosine monophosphate (cAMP)-dependent protein kinase inhibitor H-89 partially blocked the inhibitory effects of PGE(2) on CCL27 production and NF-kappaB activity, and the addition of both completely abrogated the inhibition. PGE(2) or EP3 agonist increased intracellular Ca(2+) concentrations. PGE(2) or EP2 agonist increased intracellular cAMP concentrations.

CONCLUSION

PGE(2) might suppress CCL27 production by inhibiting NF-kappaB activity through EP2-mediated cAMP and EP3-mediated Ca(2+) signals. PGE 2 might terminate T cell-mediated skin inflammation by inhibiting CCL27 production.

Practical management of psoriasis in the elderly: epidemiology, clinical aspects, quality of life, patient education and treatment options

Psoriasis in the elderly will constitute a significant challenge for the practising physician in this new millennium. Special considerations for the elderly include drug-induced or drug-aggravated psoriasis, especially for patients receiving polypharmacy or with recent worsening or poor response to conventional therapy. Other frequently encountered forms of psoriasis in the elderly include psoriatic arthritis and its complications, inverse psoriasis and potentially life-threatening complications such as erythrodermic or acute pustular psoriasis, where early recognition and systemic therapy is critical. Faced with an array of topical and systemic drug therapy options, it is of paramount importance that the physician remains focused on the holistic management of the patient, in order to achieve optimal compliance and benefit. This can be achieved through careful attention to quality-of-life issues, especially since many elderly patients may have other medical, social and economic comorbidities that can further negatively affect their overall quality of life. It is also essential that the severity of psoriasis be assessed on a more balanced, holistic scale that incorporates both physical and psychological parameters, such as the Salford Psoriasis Index. The patient and caregiver education should be multi-faceted, regularly conducted and practically orientated. Treatment goals should be kept simple and individualised for each patient, based on concomitant comorbidities, potential adverse effects, existing quality of life, self-care capability, drug history, caregiver situation, financial needs, feasibility for follow-up and patient's preferences. Topically applied medications, such as topical corticosteroids, salicylic acid, tar and dithranol preparations, calcipotriol and tazarotene, are the favoured first-line therapeutic options in the elderly. Narrowband ultraviolet B phototherapy is also well established as a standard therapy for psoriasis. Systemic therapy with agents such as methotrexate, acitretin and cyclosporin should be judiciously reserved for severe, extensive cases in view of their lower therapeutic index in the elderly. The ambulatory psoriasis treatment centre is an integral part of the overall cost-effective management of patients with psoriasis that can function as a 'one-stop' treatment and resource centre for the elderly patient.

Comparison of antiproliferative effects of experimental and established antipsoriatic drugs on human keratinocytes, using a simple 96-well-plate assay

Pharmacological treatments for psoriasis are generally based on antiproliferative, anti-inflammatory, or differentiation-modifying activity, or a combination of two or more of these actions. Potentially new drugs for treatment of psoriasis, which act on proliferation, can be identified by screening large compound libraries in a cell proliferation model that allows for characterization of drug effects on in vitro growth of normal human keratinocytes. High-throughput programs based on biological testing of diverse collections of compounds can rapidly identify leads for potential drug candidates in the treatment of psoriasis. In this study, we describe nonradioactive measurement of keratinocyte proliferation in the exponential growth phase in a 96-well format, using a sensitive deoxyribonucleic acid-binding dye to analyze drugs that are pharmacologically active in growth inhibition. Release of lactate dehydrogenase was used to exclude cytotoxic effects. We examined a number of compounds in a test range of 10(-7) to 10(-5) M, including known antipsoriatic drugs, and experimental drugs that are potentially useful in the treatment of psoriasis. We found strong concentration-dependent growth inhibition by dithranol, an antipsoriatic compound that is presumed to target the epidermal compartment. Methotrexate, cyclosporin A, and all-trans retinoic acid did not significantly affect proliferation at therapeutically relevant concentrations. The p38 mitogen-activated protein kinase inhibitor, SB220025, and curcumin, a natural phytochemical, inhibited keratinocyte proliferation at 10(-5) M. We conclude that this assay, in combination with the previously developed assays for psoriatic differentiation, provides a useful tool for identification of antipsoriatic drugs.

The Koebner phenomenon: review of the literature

First described in 1877 as the appearance of psoriatic lesions in the uninvolved skin of psoriatic patients as a consequence of trauma, the Koebner phenomenon has since been described in numerous diseases. Other authors have tried to implicate either infections or parasitic causes as the pathogenesis of this phenomenon. Subsequent research by many authors have contributed to our poor understanding of this reaction in the hope of understanding the pathogensis of psoriasis. We present a review of the literature covering the following topics as they relate to the Koebner phenomenon: diseases that koebnerize and their possible causes, predisposing and provoking factors, type, site, depth and degree of trauma, the all or none phenomenon, time lag, site preference, medications, inhibition of koebnerization and reverse koebnerization.

Drug-induced psoriasis. Recognition and management

As psoriasis is a common skin disorder, knowledge of the factors that may induce, trigger, or exacerbate the disease is of primary importance in clinical practice. Drug intake is a major concern in this respect, as new drugs are constantly being added to the list of factors that may influence the course of the disease. Drug ingestion may result in exacerbation of pre-existing psoriasis, in induction of psoriatic lesions on clinically uninvolved skin in patients with psoriasis, or in precipitation of the disease in persons without family history of psoriasis or in predisposed individuals. In view of their relationship to drug-provoked psoriasis, therapeutic agents may be classified as drugs with strong evidence for a causal relationship to psoriasis, drugs about which there are considerable but insufficient data to support the induction or aggravation of the disease, and drugs that are occasionally reported to be associated with aggravation or induction. This review focuses on the most common causative agents for drug-induced, drug-triggered, or drug-aggravated psoriasis, such as beta-blockers, lithium, synthetic antimalarial drugs, nonsteroidal anti-inflammatory agents, and tetracyclines. Latency periods, pathogenetic mechanisms of action, clinical and histologic findings, and management guidelines for each drug are discussed to help clinicians to treat patients with suspected drug-influenced psoriasis.

Psoriasis and the arachidonic acid cascade

Arachidonic acid (5.8,11,14-eicosatetraenoic acid C20:4, n-6) is released from the cell membrane by the action of phospholipases on membrane phospholipids. Metabolites of arachidonic acid, which are generically termed eicosanoids, including prostaglandins, thromboxane, leukotrienes and hydroxyeicosatetraenoic acids, have been implicated as mediators or modulators of a number of physiological functions and pathological conditions in both normal and diseased human skin. Particularly, eicosanoids have been suspected to play an important role in the pathogenesis of psoriasis, because a number of phenomena observed in psoriasis can be explained, at least in part, by the action of eicosanoids. This review will focus on recent progress regarding the significance of eicosanoids in the pathogenesis of psoriasis. Recent developments in the molecular biology in the eicosanoids have renewed interest in the role of eicosanoids in psoriasis. New understanding of the etiology of psoriasis and advances in its treatment due to recent progress in eicosanoid biology will also be presented.

Selected drug complications and treatment conflicts in the presence of coexistent diseases

The presence of different coexistent systemic diseases often times complicates the selection of the appropriate treatment of an underlying rheumatologic condition. In this article, some controversial treatment conflicts that are frequently encountered in the daily practice of rheumatology are clarified and guidelines for the best available therapeutic options are provided.

Aetiology and pathogenesis of psoriasis

The hereditary transmission of psoriasis is suggested by epidemiological data and familial association, but remains incompletely defined, not appearing to follow simple autosomal dominant or recessive patterns. The confusion may be due to a multifactorial inheritance, or to inheritance of only a 'predisposition' to disease which requires an environmental stimuli for expression. Recent advances in genetic mapping indicate genetic heterogeneity, and suggest that definition of psoriasis at the level of the gene may soon be possible. Two of the three major pathogenic features of psoriasis--abnormal keratinocyte differentiation and hyperproliferation of keratinocytes--are secondary to altered growth and maturation kinetics related to the normal wound healing process. The third major pathogenic feature--infiltration of inflammatory components into the skin--can be explained by keratinocyte release of a wide variety of cytokines, immune and inflammatory modulators. Three theories have been proposed for the relationship between epidermal keratinocyte and immunocyte activation. The first theory proposes direct activation of epidermal keratinocytes by physical, chemical, or ultraviolet injury, increasing the synthesis and release of cytokines, which trigger T-lymphocyte activation in an antigen-independent fashion. The other two theories propose persistent T-lymphocyte stimulation as a result of either antigen/superantigen presentation by antigen-presenting cells, or as a result of autoreactivity. One or more of these mechanisms may be operative in different patients, at different times, or in response to different environmental stimuli. Also, the genetic heterogeneity of psoriasis suggests that different mechanisms could be linked to different genetic loci. Advances in understanding the aetiology and pathogenesis of psoriasis suggest the possibility of innovative, targeted therapies.

Pustular psoriasis precipitated by acetazolamide

We report a case of pustular psoriasis precipitated by acetazolamide, a carbonic anhydrase inhibitor. A 28-year-old man suffering from 20 years-standing generalized pustular psoriasis developed psoriatic arthritis and glaucoma and experienced a precipitation of pustular lesions and widespread erythema after initiation of oral acetazolamide for glaucoma. The cutaneous lesions and systemic symptoms improved after restriction of acetazolamide and administration of oral etretinate. Readministration of acetazolamide confirmed that generalized pustules arose within 24 hours.

Temporal infiltration of leukocyte subsets into mouse skin inflamed with phorbol ester

We have previously shown that multiple topical applications, over 11 days, of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) induces a persistent inflammatory reaction characterized by edema, cell infiltration and epidermal hyperplasia. In order to characterize the cell infiltrate during the establishment of this inflammatory reaction, immunohistochemistry was performed using two monoclonal antibodies: MOMA-2, a macrophage antibody and Thy-1, a pan T-cell antibody. The level of polymorphonuclear leukocytes (PMNs) peaked by day 3 at 160-fold over nontreated controls and then subsided to a 30-fold elevation on days 7-10. By day 4, the number of macrophages increased 2.9-fold over the nontreated control and by day 10 were elevated 6.0-fold over the nontreated control. In comparison, the number of T-cells present by day 7 was significantly elevated 9.5-fold over the nontreated group and peaked at day 8 with a 19-fold elevation relative to nontreated controls. Topical treatment of animals with hydrocortisone valerate resulted in a dramatic (> 60%) reduction in the number of T-cells present in the tissue. In contrast, there was no effect of the steroid on the number of macrophages present in the tissue. The identification of specific cell types and their time course of infiltration is consistent with the development of a chronic inflammatory lesion.

The effect of oral indomethacin on psoriasis treated with the Ingram regime

Fifty patients with psoriasis undergoing a standard Ingram regime were entered into a double-blind comparison of oral indomethacin and placebo. No significant differences were observed between the two groups in respect of disease activity or dithranol tolerance after 6 weeks.

Psoriasiform intradermal test reaction to ABPC in a patient with psoriasis and ABPC allergy

We experienced a case of psoriasis with ABPC allergy which showed a psoriasiform intradermal test reaction to ABPC. A 22-year-old man with a history of psoriasis since the age of 17 was admitted to our department because he developed erythrodermic psoriasis after oral administration of ABPC. About 1 year later, he again developed erythroderma after administration of ABPC. Intradermal testing with 2% ABPC was performed. We found infiltrating erythema at day 2, followed by a gradually increasing psoriasiform reaction at 6 days on the site of ABPC skin test. We examined the infiltrating cells in the skin test reaction immunohistochemically. Most of the infiltrating cells in the dermis were activated helper/DTH-type T cells. Among the infiltrating cells in the epidermis, we observed more cytotoxic/suppressor-type T cells than helper/DTH-type T cells. A possible role of a DH reaction to ABPC in inducing the psoriatic lesion is discussed in relation to the pathomechanisms of psoriasis.

Beta-adrenoceptor antagonist-induced psoriasiform eruption. Clinical and pathogenetic aspects

A number of beta-adrenoceptor blocking drugs have been reported to induce a papulosquamous eruption which resembles psoriasis. We report distinctive clinical, histopathologic, immunocytochemical, and electron microscopic features in beta-blocker-induced psoriasiform eruptions that differentiate this syndrome from psoriasis. Preliminary data suggest that biopsy specimens from eruptions caused by beta 1-selective adrenoceptor blocking agents (metoprolol and atenolol) were characterized by excessive degranulation of the neutrophils in the dermis, while the nonselective beta blockers (propranolol, nadolol, and sotalol) were marked by excessive release of proteolytic enzymes from macrophages, which are thought to possess beta 2-adrenergic receptors. Surprisingly, excessive release of enzymes by lymphocytes were noted in both the beta 1-selective and in the nonselective induced syndromes. It is believed that excessive lysosomal enzyme release by neutrophils, lymphocytes, and macrophages is responsible for the presence of basal keratinocyte herniations, which have previously been shown to correlate with hyperproliferation and psoriasiform changes, as well as with the presence of excessive proteolytic enzymes in the skin. It is postulated that the beta-blocker-induced syndrome may result from enhanced proliferation, motility, and activity of lymphocytes, neutrophils, and cells of the macrophage-Langerhans cell series, stemming from depressed intracellular cyclic adenosine monophosphate levels caused by the beta blockade.

Lack of effect of topical indomethacin on psoriasis

Topical 1% indomethacin had no effect on chronic stable plaque psoriasis in an open controlled study using subjective clinical scores nor in a randomised double-blind inert base controlled study using both subjective and objective measurements of lesional response; nor did it initiate or affect the development of psoriasis after cold injury. Previous studies are reviewed and it is concluded that the evidence does not support the hypothesis which relates psoriasis to eicosanoids produced by lipoxygenase activity.

Drugs in exacerbation of psoriasis

Drugs that have been associated with the precipitation or exacerbation of psoriasis include lithium, beta adrenergic receptor blocking agents, and antimalarials. The withdrawal of corticosteroids has been reported to activate pustular psoriasis. Nonsteroidal anti-inflammatory drugs, such as indomethacin, have recently been reported to exacerbate psoriasis, although additional well-controlled studies are still needed. Drugs used for treatment of psoriasis will sometimes cause a flare because of irritation, phototoxicity, or hypersensitivity reaction resulting in a Koebner phenomenon. Because psoriasis is a very complex disease and its activity is often unpredictable, clinical studies on adverse drug effects on psoriasis have been difficult to conduct. This review evaluates clinical, histologic, and biochemical evidence in the literature for drug-associated onset or exacerbation of psoriasis.

Arachidonic acid metabolism by peripheral blood cells in psoriasis

The metabolism of arachidonic acid by mixed suspensions of leukocytes and platelets prepared from peripheral blood has been studied in 20 patients with psoriasis and 21 healthy controls. A lipoxygenase-derived product, identified as 12,20-dihydroxy-5,8,10,14-eicosatetraenoic acid was formed in increased amounts by the cell suspension from the psoriatic patients. This product results from the metabolism of platelet-derived 12-hydroxy-5,8,10,14-eicosatetraenoic acid by the polymorphonuclear leukocyte 20-hydroxylase enzyme. By contrast, synthesis of the cyclo-oxygenase products 12-hydroxy-5,8,10-heptadecatrienoic acid and thromboxane B2 was diminished. Benoxaprofen, which is known to be beneficial in psoriasis, diminished the levels of 12,20-dihydroxy-5,8,10,14-eicosatetraenoic acid formed in vitro.

Prostaglandin E2 gel improvement of psoriatic lesions

Prostaglandin (PG) E2 gel and gel alone were topically applied to the psoriatic lesions of ten patients. After a few days, all PG E2-treated lesions improved, but a complete clearing, could not be achieved. Together with results from the literature, our findings strengthen the hypothesis that cyclo-oxygenase activity is endogeneously inhibited in the psoriatic plaque, thus preventing formation of PG E2 and other metabolites. Replenishing of one of these substances (E2) improved the treated lesion, thus demonstrating that a decrease of PG E2 level might be one important factor in the pathogenesis of the psoriatic lesion.

Topical application of nonsteroidal anti-inflammatory drugs prevents vehicle-induced improvement of psoriasis

In a double-blind fashion, we compared the effect of topical application of 1% indomethacin cream or 1% meclofenamate cream with the effect of vehicle therapy alone in thirty patients with psoriasis. After 4 weeks' treatment of bilaterally symmetric psoriatic plaques, the indomethacin-treated sides were worse than the vehicle-treated sides in fourteen of twenty patients (p less than 0.01); the meclofenamate-treated sides were worse than the vehicle-treated sides in seven of ten patients (p less than 0.05). We suspect that the nonsteroidal anti-inflammatory drugs contributed to the maintenance of our patients' psoriasis by altering the arachidonic acid transformation cascade.

Effects of oral meclofenamate therapy in psoriasis

One hundred three patients entered a study to evaluate the effects of oral meclofenamate sodium therapy on psoriasis. The first 4 weeks of the study were double-blind, with patients receiving either meclofenamate or placebo. Most patients receiving meclofenamate had no change in their psoriasis, in comparison with their pretherapy condition. There was no difference in the response of the psoriasis between the group taking meclofenamate and the group taking placebo. Eighty-nine patients continued in a 4-week open trial of meclofenamate. Approximately one third of the patients showed improvement, but this result appeared to be related to the open trial design. Since oral meclofenamate therapy was not associated with frequent worsening of psoriasis, it is an appropriate treatment for psoriatic arthritis.

Dermatitis herpetiformis exacerbated by indomethacin

Thirteen adults with dermatitis herpetiformis (DH) controlled by dapsone or sulphamethoxypyridazine were given indomethacin or placebo in a double-blind cross-over study. In nine of the thirteen patients the rash and pruritus of DH were exacerbated more by indomethacin than by placebo. Dapsone and sulphamethoxypyridazine requirements were increased during the indomethacin period. The involvement of lipoxygenase products in the pathogenesis of the DH skin lesions is postulated.

Modulation of epidermal cell division and growth by oxygenation products of arachidonic acid

Recently accumulated data have shown that arachidonic acid derivatives play a role not only in cutaneous inflammation, but also in regulation of epidermal growth. Today, the best evidence for the involvement of leukotrienes in human skin disease is psoriasis. Such evidence includes: the presence of leukotrienes B4, C4, and D4 and monohydroxy-eicosatetraenoic acids in psoriatic skin lesions; the presence of these compounds in amounts capable of mediating epidermal proliferation, neutrophil accumulation, and vasodilatation characteristic of psoriasis; and improvement of psoriasis by 5-lipoxygenase inhibitors.