Keloids: Animal models and pathologic equivalents to study tissue fibrosis.

Animal models are crucial for the study of fibrosis. Keloids represent a unique type of fibrotic scarring that occurs only in humans, thus presenting a challenge for those studying the pathogenesis of this disease and its therapeutic options. Here, several animal models of fibrosis currently in use are described, emphasizing recent progress and highlighting encouraging challenges.

Keloids: The paradigm of skin fibrosis - Pathomechanisms and treatment.

Keloids, fibroproliferative dermal tumors with effusive accumulation of extracellular matrix (ECM) components, particularly collagen, result from excessive expression of growth factors and cytokines. The etiology of keloids is unknown but they occur after dermal injury in genetically susceptible individuals, and they cause both physical and psychological distress for the affected individuals. Several treatment methods for keloids exist, including the combination therapy of surgical excision followed by intralesional steroid therapy, however, they have high recurrence rate regardless of the current treatment method. Improved understanding of the pathomechanisms leading to keloid formation will hopefully identify pathways that serve as specific targets to improve therapy for this devastating, currently intractable, disorder.

Epidemiologic, Clinicopathologic, Diagnostic, and Management Challenges of Pityriasis Rubra Pilaris: A Case Series of 100 Patients.

IMPORTANCE: Pityriasis rubra pilaris (PRP) is a rare papulosquamous disorder with limited epidemiologic and clinicopathologic data. Little information is available on long-term outcomes, comorbidities, and treatment efficacy. OBJECTIVE: To evaluate objective and subjective disease experience metrics from the perspectives of patients and clinicians. DESIGN, SETTING, AND PARTICIPANTS: One hundred patients with a putative diagnosis of PRP and who elected to participate completed a comprehensive survey, followed by acquisition of their medical records, including histopathology slides and reports. The data were analyzed separately from the health care clinician and the patient perspectives. Two academic dermatologists examined clinical notes, pathology reports, and photographs, confirming diagnoses via predetermined criteria. Patients were categorized into 4 levels of diagnostic certainty to allow stratification of the findings for subgroup analysis. Patients with a diagnosis of PRP were solicited through patient support organization websites. MAIN OUTCOMES AND MEASURES: Clinical outcomes, unexpected association of comorbidities, and efficacy (or lack of it) of various treatment modalities. RESULTS: Among the 100 patients, 50 were diagnosed as having classic, unquestionable PRP. The patients were a median of 61 years old (range, 5-87 years), and 46% were female. Fifty were categorized as level 1 diagnostic certainty, 15 as level 2, 30 as level 3, and 5 as level 4. Of the level 1 patients, 13 (26%) were correctly diagnosed at initial presentation; diagnosis was delayed, on average, by 29 months (range, 0.25-288 months; median, 2 months); and 27 (54%) having undergone 2 or more biopsies. At enrollment, PRP symptoms had persisted in 36 patients (72%) for an average of 58 months (range, 1-300 months; median, 30 months). Thirty-one patients (62%) had comorbidities, including hypothyroidism (20%). Nearly all patients (98%) received some form of therapy. Patients cited topical emollients, corticosteroids, and salicylic acid along with oral retinoids, methotrexate, and tumor necrosis factor inhibitors as most helpful. CONCLUSIONS AND RELEVANCE: Pityriasis rubra pilaris remains a challenging diagnosis without established and specific treatment. Our data highlight new potential avenues for research with therapeutic perspective.