Monogenic Human Skin Disorders

Human genodermatoses represent a broad and partly confusing spectrum of countless rare diseases with confluent and overlapping phenotypes often impeding a precise diagnosis in an affected individual. High-throughput sequencing techniques have expedited the identification of novel genes and have dramatically simplified the establishment of genetic diagnoses in such heterogeneous disorders. The precise genetic diagnosis of a skin disorder is crucial for the appropriate counselling of patients and their relatives regarding the course of the disease, prognosis and recurrence risks. Understanding the underlying pathophysiology is a prerequisite to understanding the disease and developing specific, targeted or individualized therapeutic approaches. We aimed to create a comprehensive overview of human genodermatoses and their respective genetic aetiology known to date. We hope this may represent a useful tool in guiding dermatologists towards genetic diagnoses, providing patients with individual knowledge on the respective disorder and applying novel research findings to clinical practice.

Extracorporeal shock wave therapy for injection site panniculitis in multiple sclerosis patients.

BACKGROUND Painful cutaneous injection site reactions may hamper treatment with interferon β (IFN-β) and glatiramer acetate (GA) in multiple sclerosis (MS) patients. OBJECTIVE To maintain therapy adherence, efficient therapeutic modalities for these subcutaneous inflammatory lesions are urgently needed. We tested the application of local extracorporeal shock wave therapy (ESWT). METHODS We applied 5 sessions of ESWT to 8 patients suffering from MS who had developed painful panniculitis at the injection sites of either IFN-β or GA. Clinical outcomes, i.e. pain reduction and regression of induration, were assessed 3 and 6 months after completion of the ESWT using a visual analogue score. RESULTS All patients showed both significant pain reduction and reduction of the skin induration in the treated lesions, while in untreated control lesions there was no improvement. CONCLUSION ESWT proved to be a non-invasive, safe and efficient physical treatment modality for injection-induced painful cutaneous side effects of disease-modifying drugs in MS. © 2014 S. Karger AG, Basel.

The dermatologists' role in managing psoriatic arthritis: results of a swiss delphi exercise intended to improve collaboration with rheumatologists.

BACKGROUND Psoriatic arthritis (PsA) substantially impacts the management of psoriatic disease. OBJECTIVE This study aimed to generate an interdisciplinary national consensus on recommendations of how PsA should be managed. METHODS Based on a systematic literature search, an interdisciplinary expert group identified important domains and went through 3 rounds of a Delphi exercise, followed by a nominal group discussion to generate specific recommendations. RESULTS A strong consensus was reached on numerous central messages regarding the impact of PsA, screening procedures, organization of the interaction between dermatologists and rheumatologists, and treatment goals. CONCLUSION These recommendations can serve as a template for similar initiatives in other countries. At the same time, they highlight the need to take into account the impact of the respective national health care system. © 2015 S. Karger AG, Basel.

Use of activity monitors for assessment of pruritus in an acute model of canine atopic dermatitis

BACKGROUND: We developed a canine model of acute atopic dermatitis to evaluate the potential of compounds to treat pruritus and skin lesions induced in Dermatophagoides farinae (Df)-sensitized dogs. HYPOTHESIS/OBJECTIVES: The aim was to investigate the effectiveness of long-term recording activity monitors to assess pruritus induced by allergen challenges. ANIMALS: Thirty-two Df-sensitized laboratory dogs. METHODS: In two blinded crossover studies, 28 Df-sensitized dogs were challenged on 3 days with a Df slurry applied to clipped abdominal skin. Dogs were treated with a positive control (prednisolone 1 mg/kg once daily for 5 days, starting 1 day before challenge) or left untreated; all were fitted with activity monitors. To confirm pruritus, a parallel study with four dogs was conducted, filming the dogs before and during challenge and assessing the film for pruritic behaviour. RESULTS: The activity of dogs treated with prednisolone was significantly lower between 00.00 and 03.00 h and between 03.00 and 06.00 h compared with untreated dogs (repeated-measures ANCOVA; P < 0.0001). To determine whether the recorded night-time activity corresponded to pruritic manifestations, we compared activity monitor and video recordings of four dogs for two periods (16.30-20.30 and 24.00-03.00 h) before and during a Df challenge. The correlation between night-time activity monitor activity and observed pruritic behaviour was highly significant (test of correlation coefficient versus zero: r = 0.57, P < 0.0001). CONCLUSIONS AND CLINICAL IMPORTANCE: Determination of night-time activity with activity monitors after allergen challenge appears to be an objective and practical way to assess pruritus in this experimental model of canine atopic dermatitis.

EGFR inhibitors erlotinib and lapatinib ameliorate epidermal blistering in pemphigus vulgaris in a non-linear, V-shaped relationship.

Novel insights into intra-cellular signalling involved in pemphigus vulgaris (PV), an autoimmune blistering disease of skin and mucous membranes, are now revealing new therapeutic approaches such as the chemical inhibition of PV-associated signals in conjunction with standard immunosuppressive therapy. However, extensive inhibition of signalling molecules that are required for normal tissue function and integrity may hamper this approach. Using a neonatal PV mouse model, we demonstrate that epidermal blistering can be prevented in a dose-dependent manner by clinically approved EGFR inhibitors erlotinib and lapatinib, but only up to approximately 50% of normal EGFR activity. At lower EGFR activity, blisters again aggravated and were highly exacerbated in mice with a conditional deletion of EGFR. Statistical analysis of the relation between EGFR activity and the extent of skin blistering revealed the best fit with a non-linear, V-shaped curve with a median break point at 52% EGFR activity (P = 0.0005). Moreover, lapatinib (a dual EGFR/ErbB2 inhibitor) but not erlotinib significantly reduced blistering in the oral cavity, suggesting that signalling mechanisms differ between PV predilection sites. Our results demonstrate that future clinical trials evaluating EGFR/ErbB2 inhibitors in PV patients must select treatment doses that retain a specific level of signal molecule activity. These findings may also be of relevance for cancer patients treated with EGFR inhibitors, for whom skin lesions due to extensive EGFR inhibition represent a major threat.

Comparative assessment of a canine-specific medium to support colony formation from canine hair follicular keratinocytes.

BACKGROUND Follicular stem cells and their progeny are responsible for the cyclical renewal of hair follicles and maintenance of the hair coat. The understanding of pathways involved in this process is essential to elucidate the pathogenetic mechanisms of primary alopecia. Stem cells and their direct descendants are located in the bulge region of the isthmus of hair follicles. Although these cells have been studied extensively in mice and humans, data for canine isthmic keratinocyte activation and proliferation are not available. HYPOTHESIS/OBJECTIVES The aim was to establish an accurate and reliable in vitro system to study the growth potential of canine isthmic keratinocytes. We assessed the colony-promoting capability of a commercially available canine-specific medium, CELLnTEC (CnT-09), compared with a well-established home-made medium, complete FAD (cFAD). The CnT-09 medium is specific for the growth of canine keratinocytes, while the cFAD medium can support growth and colony formation of keratinocytes from several species. ANIMALS Skin biopsies were obtained from 15 recently euthanized dogs of various breeds with no skin abnormalities. METHODS The isthmic region of compound hair follicles was isolated by microdissection and cell growth monitored using several parameters with colony-forming assays. RESULTS The CnT-09 and cFAD media provided similar growth as measured by the total number and size of colonies, as well as rate of cell differentiation. CONCLUSIONS The commercial canine-specific CnT-09 medium was comparable to the home-made cFAD medium in supporting the growth and proliferation of canine follicular keratinocytes in vitro. The CnT-09 medium should be a viable alternative growth medium for molecular studies of alopecic disorders in dogs.

Nonthymoma-associated exfoliative dermatitis in 18 cats.

BACKGROUND Exfoliative dermatitis has been described in cats as a paraneoplastic skin disease associated with thymoma. There are anecdotal reports of cases without thymoma, with various suspected aetiologies. HYPOTHESIS/OBJECTIVES To identify common features, underlying causes, response to therapy and outcome of nonthymoma-associated exfoliative dermatitis in cats. METHODS Retrospective analysis was carried out of cases presented to dermatology referral centres or cases submitted for histopathological examination. Detailed historical and clinical data were obtained and evaluated statistically. Histopathology was reviewed in a blinded fashion by three dermatopathologists, and PCR for herpesvirus was performed. RESULTS Eighteen cats fulfilled all inclusion criteria. There was no sex, age or breed predisposition. All cats presented with severe generalized (77%) or multifocal exfoliation (23%); 12 cats were severely depressed. In all cats, thymoma was excluded radiographically and feline leukaemia virus tests were negative. Additional imaging procedures in 14 cats and postmortem examination in two cats did not detect neoplasia. Histopathology revealed interface dermatitis, mural interface folliculitis and sebaceous adenitis indistinguishable from findings in thymoma-associated cases. PCR for herpes DNA was negative. No aetiology was identified. Treatment in 12 cases consisted of immunosuppressive doses of corticosteroids and/or ciclosporin; one responded to antibiotics, one to shampoo, two went into spontaneous remission, and two did not receive any therapy and were euthanized. CONCLUSIONS AND CLINICAL IMPORTANCE Nonthymoma-associated exfoliative dermatitis in cats is clinically and histopathologically indistinguishable from thymoma-associated cases. Most cases benefit from immunosuppressive therapy; therefore, an immunopathological response to an undefined trigger is suspected.

Estradiol-induced alopecia in five dogs after contact with a transdermal gel used for the treatment of postmenopausal symptoms in women

BACKGROUND Noninflammatory alopecia is a frequent problem in dogs. Estrogen-induced alopecia is well described in dogs, with estrogen producing testicular tumors and canine female hyperestrogenism. OBJECTIVES To increase awareness that extensive alopecia in dogs can be caused by exposure to estradiol gel used by owners to treat their postmenopausal symptoms. ANIMALS Skin biopsies from five dogs with extensive alopecia were examined. METHODS Owners were asked for a thorough case history, including possible exposure to an estradiol gel. Complete blood work and serum chemistry panel analysis were performed to investigate possible underlying causes. Formalin-fixed skin biopsy samples were obtained from lesional skin and histopathology was performed. RESULTS All owners confirmed the use of a transdermal estradiol gel and close contact with the affected dogs before development of alopecia. Histopathologic examination showed a similar picture in all five dogs. Most hair follicles were predominantly either in kenogen or telogen and hair follicle infundibula showed mild to moderate dilation. Hair regrowth was present in all five dogs after the exposure to the estradiol gel was stopped or minimized. Blood work and serum chemistry panel were within normal limits in all cases. One dog had elevated estradiol concentrations, whereas in another dog estradiol concentrations were within normal limits. CONCLUSION AND CLINICAL IMPORTANCE Alopecia can occur after contact with a transdermal gel used as treatment for postmenopausal symptoms in women. Estradiol gel used by female owners therefore represents a possible cause for noninflammatory alopecia in dogs. Estradiol concentrations are not necessarily elevated in affected dogs.

Is "milk crust" a transient form of golden retriever ichthyosis?

BACKGROUND A recessive inherited form of lamellar ichthyosis is well recognized in golden retrievers. In this breed, young puppies demonstrate a self-limiting scaling disorder which is commonly recognized by breeders, who use the term "milk crust" to describe this syndrome. HYPOTHESIS/OBJECTIVES To determine whether "milk crust" is a new keratinization disorder or a self-limiting form of golden retriever ichthyosis. ANIMALS A total of 179 golden retriever dogs (21 dams and 158 puppies) were examined. METHODS Dermatological examination and assessment of the patatin-like phospholipase-1 (PNPLA1) genotype by PCR testing of buccal mucosal swabs. Skin biopsies from one affected puppy were evaluated for histopathological abnormalities. RESULTS Forty-five of 158 (28%) puppies exhibited scaling at 8 weeks of age; 113 of 158 (72%) were dermatologically normal. Of 144 analysed samples, 40 of 144 (28%) puppies demonstrated a homozygous mutation of the PNPLA1 genotype [of which, 36 of 40 (90%) had signs of scaling], 77 of 144 (53%) demonstrated a heterozygous mutation and 27 of 144 (19%) were a normal wild-type. In six of 17 (35%) dams, a homozygous mutation of the PNPLA1 genotype was found, eight of 17 (47%) demonstrated a heterozygous mutation and three of 17 (18%) were normal wild-type. Dams with a homozygous mutation were clinically unaffected. A 1 year follow-up revealed that 23 of 28 (82%) puppies affected with this syndrome failed to develop typical signs of ichthyosis. In five of 28 (18%) dogs there was persistence of mild scaling. CONCLUSIONS AND CLINICAL IMPORTANCE We hypothesize that the clinical syndrome termed "milk crust" could represent a transient form of golden retriever ichthyosis. Remission is not fully linked to PNPLA1 genotype, suggesting that unknown factors may contribute to the clinical disease.

Canakinumab in adults with steroid-refractory pyoderma gangrenosum

BACKGROUND Pyoderma gangrenosum (PG) is a rare, neutrophilic, ulcerative skin disease that is difficult to treat, especially when unresponsive to steroids. OBJECTIVES To determine whether canakinumab is an effective and safe treatment in PG. METHODS Five adult patients with clinically and histologically confirmed steroid-refractory PG were enrolled in this prospective open-label study. They received canakinumab 150 mg subcutaneously at week 0 with an optional 150 mg at week 2 in case of an inadequate response [Physician's Global Assessment (PGA) ≥ 2], and an optional 150-300 mg at week 8 depending on PGA. The primary clinical end point was clinical improvement (PGA at least -1 from baseline) and/or complete remission (PGA 0 or 1) at week 16. Real-time quantitative polymerase chain reaction was performed on skin samples to quantify cytokine mRNA levels. RESULTS Interleukin (IL)-1β and its known target genes IL6, CXCL8 and IL36A were significantly increased in lesional skin of PG. Under canakinumab therapy, four of five patients showed a decrease in target-lesion size, PGA and Dermatology Life Quality Index (DLQI), and three of five achieved complete remission. The mean diameter of target lesions decreased from 4·32 ± 2·6 cm at visit 1 to 0·78 ± 1·3 cm at visit 7 (P = 0·03). Mean DLQI decreased from 15 ± 5 at visit 1 to 8 ± 4 by visit 7 (P = 0·01). Adverse effects were reported in two patients: fatigue in one and worsening of disease at a nontarget lesion in the other. CONCLUSIONS Our data indicate that IL-1β plays a key pathogenic role in PG and canakinumab may represent a therapeutic option for steroid-refractory PG.

Successful Treatment of Recalcitrant Prurigo with Alitretinoin

BACKGROUND Chronic itch with secondary scratch lesions such as prurigo has a major impact on quality of life. Due to its relapsing nature and often unknown origin, its treatment is challenging. OBJECTIVE We sought to demonstrate that alitretinoin can be an efficacious and well-tolerated treatment in a patient suffering from chronic itch with concomitant prurigo and psoriatic lesions. METHODS Case report. RESULTS After 1 month of alitretinoin treatment (30 mg daily), itch as well as prurigo and psoriasis lesions decreased markedly. Three cycles of alitretinoin were administered, as each cessation of treatment led to relapse of the symptoms after 6-8 weeks. Tapering of the alitretinoin dose (30 mg every second day) after the third cycle allowed to maintain the effects for over 18 months. CONCLUSION Treatment of refractory prurigo with alitretinoin might be an efficacious alternative to standard therapies. In case of relapse, retreatment with alitretinoin reinduces a further long-lasting response.