Phuong Khuu, M.D., is a Clinical Assistant Professor in Pediatric Dermatology at Lucile Packard Children’s Hospital. Her clinical interests include children with complex dermatologic diseases and epidermolysis bullosa. Her research interest is in clinical management of epidermolysis bullosa.
- Pediatric Dermatology
- Complex Dermatologic Diseases
- Epidermolysis Bullosa
Clinical Assistant Professor, Dermatology
Residency: University of California San Francisco (2005) CA
Internship: University of California San Francisco (2003) CA
Medical Education: University of California at San Francisco School of Medicine (2002) CA
Residency: Stanford University Hospital and Clinics - Dermatology Department (2010) CA
Fellowship: Stanford University (2007) CA
Board Certification: American Board of Dermatology, Dermatology (2011)
Gene Transfer for Recessive Dystrophic Epidermolysis Bullosa
This trial will create a skin graft, which the investigators call "LEAES," using the patient's own skin cells that have been genetically engineered in the lab to express a missing protein called type VII collagen. The corrected cells will be transplanted back to the patient.
Stanford is currently not accepting patients for this trial. For more information, please contact Yana Dutt-Singkh, 650-721-7166.
Grafting of Epidermolysis Bullosa Wounds Using Cultured Revertant Autologous Keratinocytes
The term epidermolysis bullosa (EB) is used to describe a group of genetic skin diseases associated with skin weakness, blisters, and chronic wounds. "Revertant mosaicism" means that there are two genetically different populations of cells due to spontaneous mutations. Some EB patients have normal, non-fragile skin patches which may be areas of revertant mosaicism. In the revertant areas, the proteins function normally, like non-EB skin. In this study, we plan to culture cells from the revertant areas and graft them on to the wounded areas.
Stanford is currently not accepting patients for this trial. For more information, please contact Emily S Gorell, MS, 650-721-7166.
A retrospective analysis of diagnostic testing in a large North American cohort of patients with epidermolysis bullosa.
Journal of the American Academy of Dermatology
BACKGROUND: Accurate diagnosis of epidermolysis bullosa (EB) has significant implications for prognosis, management, and genetic counseling.OBJECTIVE: To describe diagnostic testing patterns and assess diagnostic concordance of transmission electron microscopy (TEM), immunofluorescence mapping (IFM), and genetic analysis for EB.METHODS: A retrospective cohort of patients enrolled in the Epidermolysis Bullosa Clinical Characterization and Outcomes Database from January 1, 2004 to July 8, 2019 was included. Tests concluding the same EB type (EB simplex [EBS], junctional EB [JEB], dominant dystrophic EB [DDEB], recessive dystrophic EB [RDEB]) were considered concordant, different EB types discordant, and non-specific/non-definitive results equivocal.RESULTS: A total of 970 diagnostic tests were conducted from 1984 to 2018 in 771 patients. Genetic analyses were performed chronologically later than IFM or TEM (p<.001). The likelihood of undergoing genetic analysis was greater for JEB and RDEB, and the same for DDEB as compared to EBS. TEM results in 163 patients were equivocal (55%), concordant (42%), and discordant (3%). IFM results in 185 patients were equivocal (54%), concordant (42%), and discordant (4%).LIMITATIONS: Retrospective design.CONCLUSION: Diagnostic testing has shifted in favor of genetic analysis. TEM and IFM frequently offer equivocal findings when compared to the specificity afforded by genetic analysis.
View details for DOI 10.1016/j.jaad.2021.09.065
View details for PubMedID 34634382
Physiotherapy for epidermolysis bullosa: clinical practice guidelines.
Orphanet journal of rare diseases
2021; 16 (1): 406
Epidermolysis bullosa (EB) is characterized by skin fragility with blister formation occurring spontaneously or following minor trauma such as gentle pressure or friction. Current physiotherapy practice is based on anecdotal care, clinical expertise and creative problem solving with caregivers and individuals with EB. Evidence based intervention is needed to establish a foundation of knowledge and to guide international practitioners to create and improve standards of care to effectively work with individuals living with EB. This clinical practice guideline (CPG) was created for the purpose of providing evidence based interventions and best clinical practices for the physiotherapy management of individuals with EB. A survey was conducted within the EB community and six outcomes were identified as a priority to address in physiotherapy management, including (1) attaining developmental motor milestones, (2) identifying safe and functional mobility in the natural environment, (3) encouraging ambulation endurance, (4) supporting safe ability to bear weight, (5) improving access to physiotherapy services, and (6) optimizing interaction with the community. A systematic literature review was conducted and articles were critically analyzed by an international panel consisting of thirteen members: healthcare professionals (including physiotherapist, doctors, and occupational therapist), caregivers, and individuals with EB. Recommendations were formulated from evidence and panel consensus. An external panel of twelve were invited to improve the quality and gather feedback on draft manuscript and recommendations. This CPG describes the development of recommendations for physiotherapy management including several best practice interventions. This guideline lays the foundational work for physiotherapist throughout the world to provide high quality services while improving and maintaining functional mobility and independence within the EB community. The CPG outlines limitations in the evidence available and possible future research needed to improve physiotherapy practice.
View details for DOI 10.1186/s13023-021-01997-w
View details for PubMedID 34593011
Multidisciplinary Care of Epidermolysis Bullosa during the COVID-19 Pandemic - Consensus: Recommendations by an International Panel of Experts.
Journal of the American Academy of Dermatology
View details for DOI 10.1016/j.jaad.2020.06.1023
View details for PubMedID 32682031
Phase 1/2a clinical trial of gene-corrected autologous cell therapy for recessive dystrophic epidermolysis bullosa.
2019; 4 (19)
BACKGROUNDRecessive dystrophic epidermolysis bullosa (RDEB) patients have mutations in the COL7A1 gene and thus lack functional type VII collagen (C7) protein; they have marked skin fragility and blistering. This single-center phase 1/2a open-label study evaluated the long-term efficacy, safety, and patient-reported outcomes in RDEB patients treated with gene-corrected autologous cell therapy.METHODSAutologous keratinocytes were isolated from participant skin biopsies. Epidermal sheets were prepared from cells transduced with a retrovirus carrying the full-length human COL7A1 gene. These gene-corrected autologous epidermal sheets measured 5 * 7 cm (35 cm2) and were transplanted onto 6 wound sites in each of 7 adult participants (n = 42 sites total) from 2013 to 2017. Participants were followed for 2 to 5 years.RESULTSNo participants experienced any serious related adverse events. Wound healing of 50% or greater by Investigator Global Assessment was present in 95% (36 of 38) of treated wounds versus 0% (0 of 6) of untreated control wounds at 6 months (P < 0.0001). At year 1, 68% (26 of 38) of treated wounds had 50% or greater healing compared with 17% (1 of 6) of control wounds (P = 0.025). At year 2, 71% (27 of 38) of treated wounds had 50% or greater healing compared with 17% (1 of 6) of control wounds (P = 0.019).CONCLUSIONC7 expression persisted up to 2 years after treatment in 2 participants. Treated wounds with 50% or greater healing demonstrated improvement in patient-reported pain, itch, and wound durability. This study provides additional data to support the clinically meaningful benefit of treating chronic RDEB wounds with ex vivo, C7 gene-corrected autologous cell therapy. This approach was safe and promoted wound healing that was associated with improved patient-reported outcomes.TRIAL REGISTRATIONClinicaltrials.gov identifier: NCT01263379.FUNDINGEpidermolysis Bullosa Research Partnership, Epidermolysis Bullosa Medical Research Foundation, NIH R01 AR055914, Office of Research and Development at the Palo Alto Veteran's Affairs Medical Center, and the Dermatology Foundation.
View details for DOI 10.1172/jci.insight.130554
View details for PubMedID 31578311
Occupational therapy for epidermolysis bullosa: clinical practice guidelines.
Orphanet journal of rare diseases
2019; 14 (1): 129
The purpose of this article is to summarize the Dystrophic Epidermolysis Bullosa Research Association (DEBRA) International evidence-based Clinical Practice Guidelines (CPGs) for the provision of occupational therapy (OT) for children and adults living with inherited epidermolysis bullosa (EB). This is a rare genetic disorder characterized by skin fragility leading to blister formation occurring spontaneously or following minor trauma. Current OT practice for persons with EB is based on anecdotal care, clinical expertise and trial and error with collaboration between caregiver and patient. Intervention based on research is needed to establish a foundation of knowledge to guide international practitioners to create and improve standards of care and to be able to work effectively with those living with the rare diagnosis of this condition.This CPG was created by an international panel with expertise working with persons with EB. The panel was made up of 11 members including OT's, a physiotherapist, a medical doctor, social worker, person with EB and a carer of a person with EB. It describes the development of recommendations for 5 outcomes determined by survey of persons with EB, caregivers, and experienced healthcare professionals. The outcomes include independence in activities of daily living (ADL), independence in instrumental ADL, maximization of hand function (non-surgical), fine motor development and retention, and oral feeding skills. The recommendations are supplemented with additional files that include photos and specific examples to further guide occupational therapists or, in situations where an OT is not available, other members of the healthcare team.As the disorder of EB is rare, evidence-based CPGs are needed to provide a base of knowledge and practice for OTs throughout the world with the goal of providing quality care to patients, while improving their functional independence and quality of life. In addition, this information is valuable as a basis for further research.
View details for DOI 10.1186/s13023-019-1059-8
View details for PubMedID 31174559
Assessment of the Timing of Milestone Clinical Events in Patients With Epidermolysis Bullosa From North America.
Importance: Children with epidermolysis bullosa (EB) comprise a rare population with high morbidity and mortality. An improved understanding of the clinical trajectory of patients with EB, including age at time of clinical diagnosis and major clinical events, is needed to refine best practices and improve quality of life and clinical outcomes for patients with EB.Objectives: To describe demographics, clinical characteristics, milestone diagnostic and clinical events (such as initial esophageal dilation), and outcomes in patients with EB using the Epidermolysis Bullosa Clinical Characterization and Outcomes Database and to determine what characteristics may be associated with overall EB severity and/or disease progression.Design, Setting, and Participants: This cohort study included data on patients with EB who were enrolled in the Epidermolysis Bullosa Clinical Characterization and Outcomes Database from January 1, 2011, to June 30, 2017; 17 participating EB centers in the United States and Canada contributed data to this study.Exposures: Type of EB, including recessive dystrophic epidermolysis bullosa (RDEB), junctional epidermolysis bullosa (JEB), dominant dystrophic epidermolysis bullosa (DDEB), and epidermolysis bullosa simplex (EBS).Main Outcomes and Measures: Demographic information, clinical characteristics (including age at onset of signs of EB and subsequent clinical diagnosis), types of diagnostic testing performed, and milestone clinical events for patients with RDEB.Results: Of 644 enrolled patients from 17 sites included in this study, 323 were male (50.2%), with a mean (SD) age of 14.4 (11.7) years; 283 (43.9%) had RDEB, 194 (30.1%) had EBS, 104 (16.2%) had DDEB, and 63 (9.8%) had JEB. Signs of disease were present at birth in 202 patients with RDEB (71.4%), 39 with JEB (61.9%), 60 with DDEB (57.7%), and 74 with EBS (38.1%). For those with signs of disease at birth, a clinical diagnosis was made at the time of birth in 135 patients with RDEB (67.0%), 31 with DDEB (52.6%), 35 with EBS, (47.3%) and 18 with JEB (46.2%). Patients with JEB had the highest rate of any confirmatory testing (51 of 63 [81.0%]), followed by RDEB (218 of 283 [77.0%]), DDEB (71 of 104 [68.3%]), and EBS (100 of 194 [51.5%]). For all types of EB, both electron microscopy and immunofluorescence microscopy were performed at younger ages than genetic analysis. Among 283 patients with RDEB, 157 (55.5%) had esophageal dilation, 104 (36.7%) had gastrostomy tube placement, 62 (21.9%) had hand surgery, 18 (6.4%) developed squamous cell carcinoma, and 19 (6.7%) died.Conclusions and Relevance: The findings suggest that diagnostic testing for EB is more common for patients with severe phenotypes. Earlier diagnostic testing may enable improved characterizations of patients so that appropriate counseling and clinical care may be offered, especially pertaining to milestone events for those with RDEB.
View details for PubMedID 30586139
Safety and Wound Outcomes Following Genetically Corrected Autologous Epidermal Grafts in Patients With Recessive Dystrophic Epidermolysis Bullosa.
2016; 316 (17): 1808-1817
Recessive dystrophic epidermolysis bullosa (RDEB) is a devastating, often fatal, inherited blistering disorder caused by mutations in the COL7A1 gene encoding type VII collagen. Support and palliation are the only current therapies.To evaluate the safety and wound outcomes following genetically corrected autologous epidermal grafts in patients with RDEB.Single-center phase 1 clinical trial conducted in the United States of 4 patients with severe RDEB with a measured area of wounds suitable for grafting of at least 100 cm2. Patients with undetectable type VII collagen keratinocyte expression were excluded.Autologous keratinocytes isolated from biopsy samples collected from 4 patients with RDEB were transduced with good manufacturing practice-grade retrovirus carrying full-length human COL7A1 and assembled into epidermal sheet grafts. Type VII collagen gene-corrected grafts (approximately 35 cm2) were transplanted onto 6 wounds in each of the patients (n = 24 grafts).The primary safety outcomes were recombination competent retrovirus, cancer, and autoimmune reaction. Molecular correction was assessed as type VII collagen expression measured by immunofluorescence and immunoelectron microscopy. Wound healing was assessed using serial photographs taken at 3, 6, and 12 months after grafting.The 4 patients (mean age, 23 years [range, 18-32 years]) were all male with an estimated body surface area affected with RDEB of 4% to 30%. All 24 grafts were well tolerated without serious adverse events. Type VII collagen expression at the dermal-epidermal junction was demonstrated on the graft sites by immunofluorescence microscopy in 9 of 10 biopsy samples (90%) at 3 months, in 8 of 12 samples (66%) at 6 months, and in 5 of 12 samples (42%) at 12 months, including correct type VII collagen localization to anchoring fibrils. Wounds with recombinant type VII collagen graft sites displayed 75% or greater healing at 3 months (21 intact graft sites of 24 wound sites; 87%), 6 months (16/24; 67%), and 12 months (12/24; 50%) compared with baseline wound sites.In this preliminary study of 4 patients with RDEB, there was wound healing in some type VII collagen gene-corrected grafts, but the response was variable among patients and among grafted sites and generally declined over 1 year. Long-term follow-up is necessary for these patients, and controlled trials are needed with a broader range of patients to better understand the potential long-term efficacy of genetically corrected autologous epidermal grafts.clinicaltrials.gov Identifier: NCT01263379.
View details for DOI 10.1001/jama.2016.15588
View details for PubMedID 27802546
Purified Type I Collagen Wound Matrix Improves Chronic Wound Healing in Patients with Recessive Dystrophic Epidermolysis Bullosa
2015; 32 (2): 220-225
Recessive dystrophic epidermolysis bullosa is a severe genetic blistering skin condition resulting in chronic wounds. Nonhealing wounds were treated over 8 weeks using a reconstituted natural purified type I collagen skin substitute. Chronic wounds were defined as nonhealing wounds present for longer than 6 months. For each patient, two chronic wounds were identified and randomized into a control or treatment group. Both groups received standard-of-care wound dressings. The treatment group received an additional type I collagen skin substitute. Wound size was measured at baseline and weeks 1, 4, and 8. Pain, pruritus, and burning and stinging were assessed. Wound cultures were obtained at baseline and thereafter as was considered clinically relevant. Ten subjects were enrolled; seven completed the study. Six subjects showed a positive response to the type I collagen skin substitute. Three subjects demonstrated full wound reepithelialization. Wounds treated using the collagen skin substitute showed statistically significantly greater improvement. Average scores for pruritus and pain decreased significantly. Reconstituted natural purified type I collagen skin substitutes improved the healing of chronic wounds and may be a valuable addition to the epidermolysis bullosa wound care arsenal.
View details for DOI 10.1111/pde.12492
View details for Web of Science ID 000351747500017
View details for PubMedID 25557742
Treatment of keratitis-ichthyosis-deafness (KID) syndrome in children: a case report and review of the literature
2015; 28 (2): 89-93
Keratitis-ichthyosis-deafness (KID) syndrome is a rare hereditary cornification disorder resulting from mutations in connexin 26, a protein important for intercellular communication. In addition to the characteristic clinical triad of congenital bilateral sensorineural hearing loss, keratitis, and erythrokeratoderma, affected individuals also suffer from chronic bacterial and fungal infections and have an increased risk of benign and malignant cutaneous tumors. Treatments with antibiotics, antifungals, and systemic retinoids have been reported with variable response. Ocular and skeletal toxicity from prolonged exposure to systemic retinoids is a major concern especially in children. We report a case of a 7-year-old boy with KID syndrome complicated by frequent infections who responded well to acitretin 0.5-1.0 mg/kg/day. The patient had significant improvement of the hyperkeratosis on the scalp, trunk, and extremities within 4 weeks after initiating treatment. The patient has been on treatment for over a year without notable ocular, skeletal, or laboratory side effects. A review of the literature focusing on therapeutic options for KID syndrome and concerns about safety and tolerability is presented.
View details for DOI 10.1111/dth.12192
View details for Web of Science ID 000352630800010
An open-label study to evaluate sildenafil for the treatment of lymphatic malformations.
Journal of the American Academy of Dermatology
2014; 70 (6): 1050-1057
Lymphatic malformations can be challenging to treat. Mainstay interventions including surgery and sclerotherapy are invasive and can result in local recurrence and complications.We sought to assess the effect of 20 weeks of oral sildenafil on reducing lymphatic malformation volume and symptoms in children.Seven children (4 boys, 3 girls; ages 13-85 months) with lymphatic malformations were given oral sildenafil for 20 weeks in this open-label study. The volume of the lymphatic malformation was calculated blindly using magnetic resonance imaging performed before and after 20 weeks of sildenafil. Lymphatic malformations were assessed clinically on weeks 4, 12, 20, and 32. Both the physician and parents evaluated the lymphatic malformation in comparison with baseline.Four subjects had a lymphatic malformation volume decrease (1.0%-31.7%). In 2 subjects, despite a lymphatic malformation volume increase (1.1%-3.7%), clinical improvement was noted while on sildenafil. One subject had a 29.6% increase in lymphatic malformation volume and no therapeutic response. Lymphatic malformations of all 6 subjects who experienced a therapeutic response on sildenafil softened and became easily compressible. Adverse events were minimal.A randomized controlled trial will be necessary to verify the effects of sildenafil on lymphatic malformations.Sildenafil can reduce lymphatic malformation volume and symptoms in some children.
View details for DOI 10.1016/j.jaad.2014.02.005
View details for PubMedID 24656411
Rapidly Involuting Congenital Hemangioma Associated with Profound, Transient Thrombocytopenia
2014; 31 (3): 402-404
Rapidly involuting congenital hemangioma (RICH) is an uncommon, often high-flow vascular tumor that presents at birth and involutes within the first year of life. It is clinically and histologically distinct from infantile hemangioma, kaposiform hemangioendothelioma, and tufted angioma, the latter two being associated with Kasabach-Merritt phenomenon. We present a female infant with RICH and profound, transient thrombocytopenia and review the extent and clinical course of thrombocytopenia in the context of congenital vascular tumors.
View details for DOI 10.1111/j.1525-1470.2012.01827.x
View details for Web of Science ID 000334884300044
View details for PubMedID 22937785
Multiple Eruptive Pilomatricomas in a 9-year-Old Boy with Glioblastoma.
2013; 30 (6): 756-758
A 9-year-old male presented to our dermatology clinic with a recent history of developing numerous cutaneous pilomatricomas, and was subsequently discovered to have sustained a recurrence of his glioblastoma multiforme. Immunohistochemical staining of a representative pilomatricoma and his original brain tumor revealed upregulation and nuclear localization of beta-catenin, a sign associated with poor prognosis in glioblastoma. We hypothesize that the development of multiple pilomatricomas may have been a hallmark of this patient's tumor recurrence and provide support for a recent report of an association between multiple pilomatricomas and gliomatosis cerebri.
View details for DOI 10.1111/j.1525-1470.2011.01714.x
View details for PubMedID 22304393
Clofarabine in refractory Langerhans cell histiocytosis
PEDIATRIC BLOOD & CANCER
2008; 51 (5): 703-706
Patients with multi-system Langerhans cell histiocytosis (LCH) who progress on frontline therapy have a dismal outcome. Responses to cladribine have been reported in relapsed LCH, but there are no well defined salvage regimens for LCH is refractory to therapy. The next generation deoxyadenosine analog, clofarabine, has demonstrated activity in patients with leukemia that is refractory to salvage regimens, including other nucleotide congeners; however, no experience exist on the use of clofarabine in LCH. In this report we describe significant single agent activity of clofarabine in disseminated LCH refractory to salvage regimens, including cladribine.
View details for DOI 10.1002/pbc.21668
View details for Web of Science ID 000259465400033
View details for PubMedID 18623218