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Background: Palmoplantar pustulosis is considered to be a localized pustular psoriasis confined to the palms and soles. Mutation of the IL36RN gene, encoding interleukin-36 receptor antagonist (IL-36Ra), is associated with generalized pustular psoriasis, but IL36RN mutations in Chinese palmoplantar pustulosis patients have not previously been investigated., Objective: The aim of this study was to evaluate the mutation of IL36RN in Chinese patients with palmoplantar pustulosis., Methods: Fifty-one Han Chinese patients with palmoplantar pustulosis were recruited. All exons and exon-intron boundary sequences of IL36RN were amplified in polymerase chain reactions, and Sanger sequencing of the amplicons was performed., Results: Among the 51 palmoplantar pustulosis patients, four different single-base substitutions were identified in nine patients. The mutations were c.140A>G/p.Asn47Ser in five patients, c.258G>A/p.Met86IIe in two patients, and c.115+6T>C and c.169G>A/p.Val57IIe in one patient each. All mutations were heterozygous. Comparison with the human genome database and reported literature suggested that these variants may not be pathogenic mutations causing palmoplantar pustulosis. Furthermore, there was no difference in disease severity, onset age, or disease duration between patients with these heterozygous IL36RN variants and those without (p>0.1)., Study Limitation: Lack of the further evaluation of IL36Ra protein in palmoplantar pustulosis lesions., Conclusions: The four variants of IL36RN identified did not appear to be associated with the specific phenotypes of palmoplantar pustulosis., (Copyright © 2019. Published by Elsevier España, S.L.U.)

Necrolytic acral erythema (NAE) is a recently recognized dermatosis almost exclusively associated with hepatitis C virus (HCV) infection, and closely related to zinc deficiency. We present the case of a 60-year-old man with a history of psoriasis and chronic HCV infection, who developed new lesions of NAE extending from previous elephantine psoriatic plaques on bilateral lower legs. According to previous reports, resolution of NAE has been successfully achieved by treatment of the underlying HCV infection, or the use of oral zinc therapy. Our patient exhibited good response to zinc therapy. By reporting this case, we would like to raise the awareness of physicians to this unique acrally distributed dermatosis, which is distinct from psoriasis by its pathological feature of aggregated necrotic keratinocytes and its good response to zinc therapy rather than topical corticosteroids., (© The Author(s) 2016.)

Background: Difficult-to-treat palmoplantar psoriasis has a disproportionately negative impact on quality of life., Objective: We evaluated the efficacy and safety of apremilast in palmoplantar psoriasis., Methods: A post hoc analysis of data pooled from phase IIb (PSOR-005) and phase III (Efficacy and Safety Trial Evaluating the Effects of Apremilast in Psoriasis [ESTEEM] 1 and 2) clinical studies was conducted to determine the effect of apremilast 30 mg twice daily versus placebo at week 16 in a subset of patients with moderate to severe plaque psoriasis with active palmoplantar psoriasis (baseline Palmoplantar Psoriasis Physician Global Assessment [PPPGA] score ≥1)., Results: Significantly more patients taking apremilast with moderate to severe palmoplantar psoriasis (baseline PPPGA score ≥3) achieved PPPGA score 0 (clear) or 1 (almost clear) compared with placebo at week 16 (48% vs 27%; P = .021). At week 16, 46% of the apremilast group with baseline PPPGA score 1 or higher achieved a PPPGA score of 0 versus 25% of the placebo group (P < .001); 59% of the apremilast group had a PPPGA score of 0 or 1 with 1-point or more improvement versus 39% receiving placebo (P < .001)., Limitations: This post hoc analysis was limited to 16 weeks and did not assess palmoplantar pustules, lesion localization, or surface area involvement., Conclusion: Apremilast may be a useful oral treatment option for patients with moderate to severe palmoplantar plaque psoriasis., (Copyright © 2016 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Background: Rubbing the skin and trauma may influence the persistence of psoriasis over time., Objectives: To assess the impact of a new fabric made with a special fluorine-synthetic fiber in improving plantar psoriasis., Methods: A total of 20 patients with symmetrical lesions were randomized to receive on one side a sock made of fluorine-synthetic fiber and on the other side a sock made of cotton fabric for 4 weeks. The main outcome was the percentage reduction of lesional area., Results: In an intention-to-treat analysis, the median lesion reduction was 11.95% in fluorine-synthetic fiber arm and 11.89% in cotton arm (p = 0.776). Among secondary outcomes, patient global satisfaction showed a statistically significant median score of 32 toward fluorine-synthetic fiber arm (p = 0.011)., Conclusion: In spite of our main negative results, it is important to continue investigating on the relation between textiles and skin disorders to improve patient well-being.

Background/aims: Rubbing the skin may influence the persistence of pustulosis over time. The aim of this study was to assess the impact of a new fabric made with fluorine-synthetic fiber in improving plantar pustulosis., Methods: A total of 17 patients were randomized to receive on one side a sock made of fluorine-synthetic fiber and on the other a sock made of cotton fabric for 4 weeks. The main outcome was the percentage reduction of lesional area at week 4., Results: The median lesion reduction at week 4 was 42.6% in the fluorine-synthetic fiber arm and 2.7% in the cotton arm (p = 0.148). Among secondary outcomes, the overall reduction over time in the treated areas was significantly in favor of the fluorine-synthetic fiber arm (p = 0.045) as well as the perception of the disease by the patient (p = 0.025)., Conclusion: Despite the fact that the primary outcome was not reached, there was a tangible reduction in the extension of the treated areas and in the perception of the disease by the patient., (© 2014 S. Karger AG, Basel.)

Background: Scarce evidence exists on the dermoscopic pattern of psoriasis on specific body sites., Objective: To describe the dermoscopic characteristics of psoriatic plaques located on the scalp, face, folds, palms, soles and genitalia., Methods: Dermoscopic images of psoriatic lesions located on the aforementioned body sites were retrospectively evaluated for the presence of predefined criteria., Results: A total of 139 lesions from 85 patients were included in the study. Dotted vessels were the commonest dermoscopic criterion (97.1%) followed by white scales (64.7%), while vessel distribution was regular in 87.7% of cases. Regularly distributed dotted vessels represented a constant finding in all locations, while the frequency of white scales varied significantly among different body sites., Conclusion: The well-known dermoscopic criteria of psoriasis can also be seen in lesions located on the scalp, face, palms, soles, folds and genitalia, with the frequency of white scales varying among different body sites., (© 2014 S. Karger AG, Basel.)

1-3% of human population is affected by psoriasis. Nail disorders are reported in 10-80% of patients with psoriasis. Nail deformations vary according to their degree of severity but are mainly represented by pitting, Beau's lines, hyperkeratosis, onycholysis, leuconychia or oil drops. Onychomycosis is a fungal infection of the nails, caused by dermatophytes, yeast and moulds. In this study, 228 patients with psoriasis aged between 18 and 72 were examined (48 - from Plovdiv, Bulgaria; 145 - from Pleven, Bulgaria and 35 - from Thessaloniki, Greece); 145 of them were male and 83 of them were female. The examination of the nail material was performed via direct microscopy with 20% KOH and nail samples plated out on Sabouraud agar methodology. The severity of the nail disorders was determined according to the Nail Psoriasis Severity Index (NAPSI). Positive mycological cultures were obtained from 62% of the patients with psoriasis (52%- Plovdiv, Bulgaria; 70%- Pleven, Bulgaria and 43%- Thessaloniki, Greece). In 67% of the cases, the infection was caused by dermatophytes, in 24% by yeast, in 6% by moulds and in 3% by a combination of causes. All patients with psoriasis were identified with high levels of NAPSI, whereas the ones with isolated Candida had even higher levels. Seventeen percentage of the patients have been treated with methotrexate, 6% have been diagnosed with diabetes and 22% have been reported with onychomycosis and tinea pedis within the family. An increased prevalence of onychomycosis among the patients with psoriasis was found. Dystrophic nails in psoriasis patients are more predisposed to fungal infections. The mycological examination of all psoriasis patients with nail deformations is considered obligatory because of the great number of psoriasis patients diagnosed with onychomycosis., (© 2011 Blackwell Verlag GmbH.)

Aim: Palmoplantar psoriasis (PPP) produces significant morbidity and requires prompt treatment. Topical agents form the mainstay of therapy. We compared the efficacy and side-effect profile of a steroid/coal-tar combination with topical psoralen and solar ultraviolet A (PUVAsol) in PPP., Methods: In total, 52 patients with PPP were randomized to receive either a combination of clobetasol propionate cream and coal tar daily (group 1) or topical PUVAsol on alternate days (group 2) for 16 weeks. Response was assessed as change in Psoriasis Activity and Severity Index (PASI) and Patient Global Assessment (PGA)., Results: Of the 52 patients, 43 completed the treatment phase. There was a reduction in PASI for the palms and soles in both treatment groups throughout the treatment period until week 16. There was a greater reduction in PASI in palmar psoriasis with topical PUVAsol, and a greater reduction in psoriasis of the soles with the steroid/coal-tar combination. In both groups, patients perceived 'good improvement'. Improvement or cure in palmar lesions was observed in 90% of cases in the topical steroid/coal-tar group and in 75% of cases in the topical PUVAsol group; for the soles, these figures were 76% and 79%, respectively. No adverse effects were experienced with the steroid/coal-tar combination, whereas for the topical PUVAsol, phototoxicity occurred in 22% of cases., Conclusion: Both treatments had comparable efficacy. In both groups, patients experienced 'good improvement' after 16 weeks of therapy., (© The Author(s). CED © 2011 British Association of Dermatologists.)

Psoriasis is a common, chronic, inflammatory disease with a wide range of clinical presentations. The disease severity ranges from mild to severe. Plaque type of psoriasis is the most common. A number of factors like previous treatment history and comorbid conditions influence the treatment of psoriasis in an individual patient. Location of the lesions is also an important consideration. Psoriasis localized to certain areas of the body like scalp, nails, palms and soles remains difficult to treat. These sites have been referred to as the difficult locations in literature. This article covers the management of psoriasis limited to these special areas.

Background: Palmoplantar pustulosis (PPP) is a chronic and intensely inflammatory skin disease with pustules, erythema and scaling localized to the palms and soles. To date, no specific treatment is known. Earlier findings indicate the acrosyringium as the target for the inflammation., Objectives: To identify specific features of the PPP inflammatory cell infiltrate and mediators of inflammation, which might provide insight into the pathogenesis and possible future treatment of the disease., Methods: Skin biopsies were taken from 23 patients with typical PPP (23 from involved skin and seven from noninvolved skin) and from 18 healthy controls (10 nonsmokers, eight smokers). Cell infiltrates and inflammation mediators were studied with immunohistochemistry., Results: A strong inflammation was observed in lesional skin of PPP. Our main findings of Langerhans cells and interleukin-17 close to or in the acrosyringium differs from findings in psoriasis vulgaris. Other inflammatory cells such as CD4+, CD8+, regulatory T cells and CD11a+ cells were also accumulated close to the sweat duct in epidermis and papillary dermis. More CD4+, CD8+, Langerhans cells, plasmacytoid dendritic cells and a higher proportion of regulatory T cells/CD3+ cells were seen in noninvolved palmar skin from patients with PPP compared with healthy controls., Conclusions: Our novel findings indicate that the inflammation in PPP is initiated by the 'stand-by' innate immune system at the acrosyringium., (© 2010 The Authors. Journal Compilation © 2010 British Association of Dermatologists.)

Hand and foot psoriasis is a disabling condition associated with significant quality-of-life issues. It is characterized by hyperkeratosis and/or the development of recurrent crops of sterile pustules with associated erythema, fissuring, and scaling symmetrically localized on palm and soles. Systemic conventional therapies include retinoids, psoralen-UVA (PUVA), methotrexate, and cyclosporine. So far, only limited evidence supports the use of TNF-alfa blockers. Because there are reports of paradoxical induction of pustular psoriasis following the use or withdrawal of infliximab as well as other TNF inhibitors, the use of these agents in palmoplantar psoriasis has been cautioned. The authors describe the clinical characteristics and evolution of 4 adult patients with severe palmoplantar psoriasis who were treated successfully with infliximab. Patient data is available for a minimum of 10 months and as many as 16. One of them with concomitant HCV infection showed no increased viral replication or progression of liver disease for a follow-up of 10 months; afterwards infliximab was stopped because of an infusion-related urticaria. All other patients displayed a good clinical response (> or =PPPASI 50) and were still receiving this regimen at last observation. This report provides preliminary evidence to support a cautious use of infliximab in patients with palmoplantar psoriasis.

Background: Palmoplantar pustular psoriasis (PPP) is difficult to treat. We assessed the effectiveness of alefacept in PPP and the safety of a 30 mg/week dose., Methods: Fifteen individuals with PPP were started on 15 mg/week intramuscularly (IM) alefacept. Efficacy was measured by the PPP severity instrument (PSI). Treatment was continued for 16 weeks, and the alefacept dose was increased to 30 mg/week IM at week 9 if the PSI did not decrease by at least 25%. Other outcomes included physician's global assessment (PGA), reported adverse events and CD4+ T-lymphocyte counts. Clinical response was observed for 12 weeks after the last injection., Results: The severity of PPP improved in both the PSI and the PGA (p<0.0001 and p = 0.0009, respectively). Much of the improvement occurred after 10 weeks of therapy. Nail severity scores improved (p = 0.0003). CD4+ counts decreased, but all remained >250 cells/mm3. There were no severe adverse effects or discontinuations due to adverse events., Conclusions: Alefacept in doses up to 30 mg/week was well tolerated in patients with PPP and appeared to have some efficacy. The use of concomitant therapy, the lack of a comparator, and the small sample size are limitations of the study.

Psoriasis of the hands and feet is highly debilitating and difficult to treat. It may be of a plaque-or pustular-type, or a combination of the two. Efalizumab (Raptiva, Genentech Inc), a humanized monoclonal antibody that inhibits critical T cell-mediated processes, is approved by the FDA for the treatment of adult patients with chronic moderate to severe plaque psoriasis. We present the cases of 7 patients who suffered from extensive hand and foot psoriasis recalcitrant to treatment. Each patient was treated with 1 mg/kg/wk of efalizumab and responded rapidly to treatment with favorable results appearing within 1 to 4 months. Patients were able to resume previous work responsibilities and no longer suffered from difficulties with ambulation. Efalizumab was effective for the rapid treatment of these 7 patients with psoriasis of the hands and feet.

Hand and foot psoriasis can appear in a plaque-type or pustular-type form. Any form of psoriasis that occurs on the hands and feet can have a debilitating effect on the patient's daily functions. Here we present a case series of patients with plaqueor pustular-type hand and foot psoriasis whose conditions were successfully managed with the biologic agent efalizumab. In many of these patients, the disease was refractory to multiple systemic psoriasis treatments. Treatment with efalizumab was effective and well-tolerated, with few adverse events. Many of the patients described here reported an improvement in both their physical functioning and health-related quality of life. The efficacy of efalizumab in treating these cases of hand and foot psoriasis suggests that it may provide therapeutic benefit.

Alefacept is the first biologic agent approved by the US Food and Drug Administration for moderate to severe chronic plaque psoriasis. Prior clinical studies excluded patients with palmoplantar psoriasis or erythroderma. We report 2 patients with recalcitrant psoriasis who responded completely to a full course of alefacept. One patient presented with severe palmoplantar psoriasis recalcitrant to acitretin and methotrexate; another patient presented with erythroderma and was transitioned successfully from cyclosporine A. Alefacept provides another treatment option for palmoplantar and erythrodermic psoriasis and should be considered in the management of patients with these conditions.

FROM A CLINICAL POINT OF VIEW: Infantile acropustulosis is a rare and little known dermatosis affecting young children. Clinically, it consists of prurigenous vesiculo-pustular lesions characteristically localised on the palms of the hands and the soles of the feet. NO CONFUSION SHOULD EXIST: The principle differential diagnosis is scabies. The other differential diagnosis is neonatal pustulosis. A CONTROVERSIAL HYPOTHESIS: The aetiopathogenesis is unknown, but some cases of infantile acropustulosis set-in in the course of a genuine scabies, which might suggest a hypersensitivity reaction to Sarcoptes scabiei. It is a benign affection, progressing in flares, occasionally provoking severe pruritus. Treatments are disappointing, and the disease heals spontaneously after a few years.

Linear psoriasis is a rare entity. It is commonly confused clinically and histopathologically with verrucous epidermal nevus. We report a child who had linear psoriasis in a unilateral distribution with palmoplantar, nail, and scalp involvement.

Palmoplantar psoriasis is a disabling condition characterized by recurrent crops of sterile pustules with associated erythema, fissuring, and scaling. Genetic and environmental factors have been implicated in its etiology. Topical treatments are frequently ineffective. Other treatment options include systemic retinoids, psoralen-UVA (PUVA), and a combination of both. We report a case of successful treatment of recalcitrant palmoplantar psoriasis with etanercept in a 59-year-old woman unresponsive to other treatment modalities.

Background: Cutaneous reactions may occur in patients receiving terbinafine therapy, mainly rash and urticaria. More exceptionally, development of psoriasis has been described. We describe the development of plantar pustular psoriasis in a patient who took oral terbinafine., Case Report: A 70-year-old man, without previously known history of psoriasis, was treated with terbinafine, 250 mg/day, for onychomycosis. Ten days later, a plantar pustular psoriasis appeared. The psoriasis cleared up after discontinuation of terbinafine and institution of antipsoriatic therapy., Discussion: Terbinafine is an antifungal agent widely use in the treatment of onychomycosis. A skin reaction occurs in 3 p. 100 of patients. Only 24 cases of flare-up of previous psoriasis or psoriasis de novo after terbinafine have been described. The psoriasis generally clears after discontinuation of terbinafine. So, terbinafine is perhaps not the best first line therapy for onychomycosis in patients with psoriasis.

A 24-year-old man with Down syndrome presented with prominent ichthyosiform skin on his extremities and psoriatic plaques on his chest, back and scalp. The late onset of his ichthyosis without family history suggested that it was not a heritable form but was associated Down syndrome. Such an association with ichthyosis and psoriasis has not been described previously.

Pustulosis palmoplantaris (PPP) is a common chronic skin disease, which is very resistant to treatment. It is not known why the lesions are located in the palms and soles. There are few studies of the disease and in particular studies of the histology. Fifty-nine patients with PPP answered a questionnaire concerning their medical history and 39 of them were clinically examined. Biopsy specimens were taken from involved skin in 22 of the 39 patients and studied immunohistologically for tryptase+ mast cells, EG2+ eosinophils, lipocalin+ neutrophils and CD3+ T lymphocytes. The sweat gland and sweat duct were visualized with AE1/AE3 antibody (cytokeratins 1-8, 10, 14/15, 16, 19). In addition to neutrophils in the pustule and lymphocytes in the upper dermis, there were also large numbers of mast cells and eosinophils in the subpustular area. Numerous eosinophils were present in the pustule. The epidermal part of the eccrine duct was not detectable in any of the specimens from patients with PPP but was present in all of the nine control persons (including two smokers). The results indicate that the acrosyringium is involved in the inflammation and also that mast cells and eosinophils participate in a hitherto unknown way. Of the 39 patients clinically examined, two had previously diagnosed thyroid disease and two had gluten hypersensitivity. Seventeen had one or several abnormal serum concentrations of thyroid-stimulating hormone, thyroxin, antibodies against thyroglobulin or thyroperoxidase and 10 had immunoglobulin (Ig) A antibodies to gliadin. The mean +/- SD for serum IgA and for eosinophil cationic protein was increased. From the questionnaire the most notable finding was that 56 of the 59 patients had been or still were smokers, all of whom had started smoking before the first signs of PPP. We hypothesize that the acrosyringium might be the target for the inflammation and that PPP is linked to autoimmune thyroid disease and smoking.

PUVA-induced acrobullous dermatosis is characterized by the occurrence of blisters on the acral extremities during PUVA therapy. The tense blisters apparently arise as a result of PUVA damage to the epidermodermal cohesion coupled with friction or trauma. They must be distinguished from phototoxic reactions induced either by UVA over-dosage or excessive psoralen uptake. We report on, two cases of acrobullous PUVA-induced dermatosis, discussing clinical features, pathophysiological aspects and differential diagnosis.

The scalp, palms and soles, and nails are problem sites in the everyday therapy of psoriasis. This article reviews the pathogenesis, differential diagnosis, and latest treatment.

A 46-year-old patient with 'locked-in syndrome' due to brainstem infarction developed symmetrically distributed, grouped erythematous cornified hemispherical papules on the fingertips and toes in 2 years. Histologically they showed psoriasiform changes. There was no evidence of internal malignancy nor a history of special drug intake. To our knowledge, such an eruption has not been previously reported.

Background: Reiter's syndrome is a disease characterized by crusted, scaling, acral and genital plaques; urethritis or cervicitis; and arthritis, which occur in genetically susceptible patients in response to any of many infections. This disease rarely occurs in women, and specific characterizations of vulvar and cervical lesions are rare., Observations: We describe a 39-year-old woman with a history of mucocutaneous candidiasis that was refractory to oral ketoconazole therapy. She presented with well-demarcated, erythematous, crusted plaques over the vulva, hands, and feet, as well as with cervical lesions and a history of conjunctivitis and iritis. Following the biopsy of characteristic skin lesions, recognition of systemic signs, and cultures that were negative for yeast, her condition was diagnosed as Reiter's syndrome., Conclusions: Reiter's syndrome of the vulva, vagina, and cervix may not be recognized because of its uncommon occurrence in women and the physician's consequent unfamiliarity with its clinical appearance in the genital area. This disease and pustular psoriasis share many common features and exist on a spectrum. A high index of suspicion and correlation of the many facets of the disease will better enable the clinician to make this diagnosis.

Psoriasis on the palms and soles is characterized by pustules, vesicles and hyperkeratotic plaques. Several studies have postulated that the pustules and vesicles are round or egg-shaped. This three-dimensional study reveals that neither pustules nor vesicles have a regular spherical morphology. The vesicles are located in the upper and middle layers of the epidermis and may exhibit dumb-bell- or banana-shaped lumina. The pustules consist of different compartments combining characteristics of a dyshidrotic vesicle with those of a microabscess of Munro.

A 35-year-old female developed generalized pustules within a short period of time. Clinically, two distinct types of pustules were observed, viz. erythematous patches studded with crops of small pustules, and isolated large pustules with a red halo. Histologically, the former were subcorneal spongiform pustules, whereas the latter were unilocular pustules involving the hair follicular infundibulum or a subcorneal unilocular pustule on the palmo-plantar skin. On the basis of the sudden appearance of the pustules without any pre-existing lesions of psoriasis and the histological findings of the spongiform pustules, we made a diagnosis of the exanthematic type of pustular psoriasis. The lesions responded in a dose-dependent fashion to oral cyclosporin.

A case of eruptive porokeratosis of Mibelli with diverse morphologic features, including circinate macular, circinate plaque and verrucous varieties is presented. No matter how variable the clinical presentation may be, the histologic hallmark of porokeratosis, the cornoid lamellae, is always present. The cornoid lamellae vary in height in relation to how prominent the thready ridge of the clinical lesion appears. Our patient also had psoriasis which initially masked the porokeratotic lesions both clinically and histologically. Awareness of the various clinical expressions of porokeratosis of Mibelli would 1) make unnecessary the segregation of certain forms of porokeratosis into separate entities, and 2) help in the recognition of less classical forms of porokeratosis.

Polymorphonuclear leukocyte (PMN) and monocyte (MN) chemotaxis in nine patients with pustulosis palmo-plantaris (PPP) and ten patients with pustular psoriasis (PP) was determined by an objective in vitro assay employing a 51Cr-labelling technique. PMN chemotaxis was significantly enhanced in both groups of patients compared with controls. MN chemotaxis was normal. There was no difference in the chemotactic responsiveness of leukocytes from patients with PPP and PP. The random migration of PMN and MN from the patients was normal. Homogenized tissue specimens from lesional skin with and without pustules, and from perilesional, normal-looking skin of PPP and PP were analysed for the presence of chemoattractant(s) for PMN. Lesional skin had considerable chemoattractant properties, but perilesional skin did not induce directed migration of PMNs.

One hundred and seven psoriatics with palmoplantar involvement were clinically examined. They were selected from 921 patients filed in 1976 with the diagnosis psoriasis. Fifty per cent of the patients with palmoplantar psoriasis had flexural changes. The frequency of palmar involvement in patients with inverse psoriasis compared to patients with psoriasis vulgaris was increased 5.3 times. Pustulosis palmoplantaris (PPP) in addition to psoriasis was diagnosed in 18 patients (17%). A dermatophyte infection was observed in 1 of 48 patients examined for tinea infection. Positive patch tests were obtained in 8 of 47 patients, 7 of whom had more than one test reaction. The result gives no evidence of tinea infection and contact allergy as important factors in maintaining palmoplantar psoriasis.