Delayed type IV hypersensitivity reaction to porcine acellular dermal matrix masquerading as infection resulting in multiple debridements.

INTRODUCTION: Delayed type IV hypersensitivity reactions are well established in the surgical setting with respect to external exposure via topical antibiotics and internal exposure via synthetic materials. In contrast, biologic matrix is derived from decellularized human or animal tissues and is consequently believed to elicit a minimal host inflammatory response. OBJECTIVE: We report a case of delayed type IV hypersensitivity reaction secondary to a biologic comprised of porcine-derived acellular dermal matrix, [Strattice™]. CONCLUSIONS: While biologic matrix is often preferred over synthetic mesh due to its decreased risk for infection, this case emphasizes that potential for hypersensitivity to the material persists. Type IV hypersensitivity reactions should be included in the differential diagnosis for suspected post-operative infections.

Hypersensitivity Reactions to Implanted Metal Devices: Facts and Fictions.

The use of metals in the medical field has become increasingly prevalent over the past few decades. Patients find themselves being exposed to metals in a variety of ways, ranging from external exposure to instruments such as the stainless steel in surgical blades to internal exposure via medical devices being implanted in their bodies. There has been growing interest in the possibility of developing hypersensitivity reactions to constituent metals in medical implant devices, both in cutaneous and systemic forms. Hypersensitivity reactions to metals are uncommon, but they are reported and require appropriate evaluation and management, particularly if they are symptomatic. In view of the lack of consensus in the field on the appropriate steps to evaluate and manage patients with suspected metal hypersensitivity reactions, this review aims to analyze current evidence on hypersensitivity reactions to metallic implants in orthopedic surgery, endovascular surgery, obstetrics and gynecology, and dental surgery.

The imagined itch: brain circuitry supporting nocebo-induced itch in atopic dermatitis patients.

BACKGROUND: Psychological factors are known to significantly modulate itch in patients suffering from chronic itch. Itch is also highly susceptible to both placebo and nocebo (negative placebo) effects. Brain activity likely supports nocebo-induced itch, but is currently unknown. METHODS: We collected functional MRI (fMRI) data from atopic dermatitis (AD) patients, in a within-subject design, and contrast brain response to nocebo saline understood to be allergen vs open-label saline control. Exploratory analyses compared results to real allergen itch response and placebo responsiveness, evaluated in the same patients. RESULTS: Nocebo saline produced greater itch than open saline control (P < 0.01). Compared to open saline, nocebo saline demonstrated greater fMRI response in caudate, dorsolateral prefrontal cortex (dlPFC), and intraparietal sulcus (iPS) - brain regions important for cognitive executive and motivational processing. Exploratory analyses found that subjects with greater dlPFC and caudate activation to nocebo-induced itch also demonstrated greater dlPFC and caudate activation, respectively, for real allergen itch. Subjects reporting greater nocebo-induced itch also demonstrated greater placebo reduction of allergen-evoked itch, suggesting increased generalized modulation of itch perception. CONCLUSIONS: Our study demonstrates the capacity of nocebo saline to mimic both the sensory and neural effects of real allergens and provides an insight to the brain mechanisms supporting nocebo-induced itch in AD, thus aiding our understanding of the role that expectations and other psychological factors play in modulating itch perception in chronic itch patients.

Complementary integrative approach for treating pruritus.

Complementary and alternative medicine (CAM) is a conservative and increasingly popular approach to treat pruritus for both patients and medical providers. CAM includes natural products, mind-body medicine, and manipulative and body-based practices. In this overview, we summarize current evidence, possible mechanisms and clinical approaches for treating pruritus with CAM techniques. We focus on pruritus associated with atopic dermatitis, herpes zoster, chronic urticaria, burns, and postoperative contexts where the evidence for CAM approaches is promising.

Acupuncture compared with oral antihistamine for type I hypersensitivity itch and skin response in adults with atopic dermatitis: a patient- and examiner-blinded, randomized, placebo-controlled, crossover trial.

BACKGROUND: Itch is the major symptom of atopic dermatitis (AD). Acupuncture has been shown to exhibit a significant effect on experimental itch in AD. Our study evaluated acupuncture and antihistamine itch therapy (cetirizine) on type I hypersensitivity itch and skin reaction in AD using a patient and examiner-blinded, randomized, placebo-controlled, crossover trial. METHODS: Allergen-induced itch was evaluated in 20 patients with AD after several interventions in separate sessions: preventive (preceding) and abortive (concurrent) verum acupuncture (VAp and VAa), cetirizine (10 mg, VC), corresponding placebo interventions (preventive, PAp, and abortive, PAa, placebo acupuncture; placebo cetirizine pill, PC) and a no-intervention control (NI). Itch was induced on the forearm and temperature modulated over 20 min, using our validated model. Outcome parameters included itch intensity, wheal and flare size and the D2 attention test. RESULTS: Mean itch intensity (SE: 0.31 each) was significantly lower following VAa (31.9) compared with all other groups (PAa: 36.5; VC: 36.8; VAp: 37.6; PC: 39.8; PAp: 39.9; NI: 45.7; P < 0.05). There was no significant difference between VAp and VC (P > 0.1), although both therapies were significantly superior to their respective placebo interventions (P < 0.05). Flare size following VAp was significantly smaller (P = 0.034) than that following PAp. D2 attention test score was significantly lower following VC compared with all other groups (P < 0.001). CONCLUSIONS: Both VA and cetirizine significantly reduced type I hypersensitivity itch in patients with AD, compared with both placebo and NI. Timing of acupuncture application was important, as VAa had the most significant effect on itch, potentially because of counter-irritation and/or distraction. Itch reduction following cetirizine coincided with reduced attention.

Pragmatic approach to the clinical work-up of patients with putative allergic disease to metallic orthopaedic implants before and after surgery.

Allergic complications following insertion of metallic orthopaedic implants include allergic dermatitis reactions but also extracutaneous complications. As metal-allergic patients and/or surgeons may ask dermatologists and allergologists for advice prior to planned orthopaedic implant surgery, and as surgeons may refer patients with complications following total joint arthroplasty for diagnostic work-up, there is a continuous need for updated guidelines. This review presents published evidence for patch testing prior to surgery and proposes tentative diagnostic criteria which clinicians can rely on in the work-up of patients with putative allergic complications following surgery. Few studies have investigated whether subjects with metal contact allergy have increased risk of developing complications following orthopaedic implant insertion. Metal allergy might in a minority increase the risk of complications caused by a delayed-type hypersensitivity reaction. At present, we do not know how to identify the subgroups of metal contact allergic patients with a potentially increased risk of complications following insertion of a metal implant. We recommend that clinicians should refrain from routine patch testing prior to surgery unless the patient has already had implant surgery with complications suspected to be allergic or has a history of clinical metal intolerance of sufficient magnitude to be of concern to the patient or a health provider. The clinical work-up of a patient suspected of having an allergic reaction to a metal implant should include patch testing and possibly in vitro testing. We propose diagnostic criteria for allergic dermatitis reactions as well as noneczematous complications caused by metal implants.

Predictive value of a 1-day, 1-eye trial on the 1-month ocular hypotensive response of latanoprost 0.005%.

PURPOSE: To determine if a 1-day, 1-eye trial of latanoprost 0.005% was predictive of the 1-month intraocular pressure response in patients with uncontrolled open-angle glaucoma on maximally tolerated medical therapy without latanoprost. METHODS: One eye of 39 consecutive patients was enrolled in prospective trial of latanoprost 0.005%. An investigator masked to treatment eye and intraocular pressure result measured intraocular pressure at 1 day and 1 month after treatment. The diagnostic precision of the 1-day, 1-eye trial for the 1-month result was determined at a 10%, 20%, and 30% reduction from baseline intraocular pressure. RESULTS: Treatment produced a mean +/- SD (range) decrease in intraocular pressure from 20.9 +/- 4.6 (14 to 35) mm Hg to 16.6 +/- 3.6 (9 to 26) mm Hg at 24 hours (P <.0001, paired t test). This reduction in intraocular pressure was similar at 1 month with mean +/- SD (range) intraocular pressure of 16.1 +/- 3.1 (9 to 22) mm Hg (P <.0001, paired t test). The accuracy of the 1-day, 1-eye trial for the 1-month response at a 10%, 20%, and 30% reduction of intraocular pressure from baseline intraocular pressure was 96% (chi square = 29.5, P <.001), 74% (chi square = 8.4, P =.004), and 80% (chi square = 10.2, P =.001), respectively. CONCLUSION: A 1-day, 1-eye trial of latanoprost 0.005% is predictive of the 1-month intraocular pressure response in patients with uncontrolled open-angle glaucoma.

Prevalence of gold sensitivity in asymptomatic individuals with gold dental restorations.

BACKGROUND: The clinical relevance of positive patch test reactions to gold sodium thiosulfate in asymptomatic individuals with gold dental restorations is often unclear. Knowledge of the prevalence of gold sensitivity in individuals with and without gold dental restorations is required to better understand the relevance of these reactions. OBJECTIVE: To determine the prevalence of positive patch test reactions to gold in asymptomatic individuals with gold dental restorations (gold patients) compared with similar individuals without gold dental appliances (nongold patients). METHODS: One hundred thirty-six healthy, asymptomatic patients were patch tested to gold sodium thiosulfate, nickel sulfate and palladium chloride. Readings occurred after 2 days and 7 days. RESULTS: Of the patients tested, 24 of 71 (33.8%) gold patients had a positive reaction to gold versus 7 of 65 (10.8%) of the nongold patients, P <.001. Of those with a positive gold reaction, 12 of 31 (38.7%) also had a positive nickel reaction. Nickel alone was positive in 18 of 71 (25. 4%) of gold patients versus 11 of 65 (16.9%) of nongold patients. 19 of 29 (65.5%) of those with a positive nickel reaction also reacted to palladium and 19 of 22 (86.4%) of those with a palladium reaction also reacted to nickel. The rate of allergy to gold computed over a 3-year period for patients patch tested in the Oregon Health Sciences University (OHSU) Contact Dermatitis Clinic was 13.5% (46/342). CONCLUSIONS: The prevalence of gold sensitivity in individuals with gold dental restorations is approximately 33.8%. This is significantly greater than the 10.8% prevalence seen in individuals without gold dental appliances, as well as greater than the 3-year rate from the OHSU Contact Dermatitis Clinic. This data should help shed light on issues of clinical relevance.