True photoallergy to sunscreens is rare despite popular belief

BACKGROUND

Rising use of sunscreen products has led to increased reporting of adverse reactions to sunscreens.

OBJECTIVE

To investigate possible photoallergic reactions in patients who identified themselves as "being allergic" to sunscreens.

METHODS

Patients filled out questionnaires about types of sunscreens they used and timing of their "allergic" reactions. Next, they consented to be photopatch-tested with active sunscreen ingredients, including the new sunscreen Anthelios SX (containing Mexoryl SX) and the new ultraviolet filters Tinosorb M and Tinosorb S. Standard allergen patch testing was also done.

RESULTS

Twenty-seven patients self-reported "sunscreen allergy." Photopatch testing is difficult for patients; hence, only 11 agreed to proceed with the testing. Eight patients had negative patch testing results. One patient reacted to benzophenone-2. Another had a prior reaction to titanium dioxide and titanium oxalate but did not react to the silicone-coated titanium in our study. Yet another patient had relevant photopatch reactions to benzophenone-3 and ethylhexyl dimethyl para-aminobenzoic acid (PABA). None reacted to the Tinosorbs or Anthelios SX. Few positive reactions to the standard allergens were not relevant.

CONCLUSION

Although small, this study parallels prior studies in concluding that true delayed type IV hypersensitivity (allergic contact dermatitis and photoallergy) to sunscreens is more infrequent than patients tend to believe.

Methemoglobinemia After Fiberoptic Intubation in a Patient With an Unstable Cervical Fracture

Methemoglobinemia, a condition associated with cyanosis and diminished pulse oximetry values, has been reported after use of local anesthetics to facilitate fiberoptic intubation. The majority of reports in the literature detail this development during diagnostic procedures such as endoscopy and bronchoscopy. A case of methemoglobinemia in a multiple-injury patient with an unstable compressive-flexion injury of the cervical spine undergoing fiberoptic intubation is presented. A literature review of this entity is also presented. The patient underwent fiberoptic intubation using topical pharyngeal anesthetics before planned cervical corpectomy, strut grafting and instrumentation. He became acutely cyanotic with abruptly diminished pulse oximetry readings. Subsequent blood gas analysis demonstrated methemoglobinemia. Intravenous methylene blue administration led to an uncomplicated resolution of the condition. Surgeons and anesthesiologists who manage such patients should be aware of methemoglobinemia, a rare but potentially fatal complication related to topical airway anesthetics.

Pharmacological Profiles of the Novel Analgesic M58996 in Rat Models of Persistent and Neuropathic Pain

We investigated the effects of 4-(N-{1-[2-(4-cyanophenyl)ethyl]-4-hydroxypiperidin-4-ylmethyl}-N-methylamino)benzoic acid monohydrochloride (M58996), a novel analgesic, on persistent and neuropathic pain in rats. In the formalin test, oral M58996 (0.3 - 10 mg/kg) reduced nociceptive behaviors only in the late phase. In the neuropathic pain model, oral M58996 (1 - 10 mg/kg) attenuated mechanical allodynia and heat hyperalgesia in the nerve-injured paw without affecting normal responses of the uninjured paw. High doses (10 - 100 mg/kg) of oral M58996 did not influence normal motor function. Thus, M58996 had a wide dose range showing antinociceptive, antiallodynic, and antihyperalgesic effects without motor dysfunction. In addition, we studied the possible mechanisms involved in the M58996-induced antinociception. The antinociceptive effect of M58996 was reversed by intrathecal pertussis toxin, an inhibitor of the inhibitory- and other-GTP-binding protein (G(i/o) protein), but not by subcutaneous naloxone, an opioid-receptor antagonist. This effect was also reversed by intracerebroventricular or intrathecal tropisetron, a 5-hydroxytryptamine(3) (5-HT(3))-receptor antagonist, and intraperitoneal bicuculline, a gamma-aminobutyric acid(A) (GABA(A))-receptor antagonist. These results suggest that M58996 produces its antinociceptive effect by a pertussis toxin-sensitive G protein mechanism. In addition, the GABA released by the activation of supraspinal and/or spinal 5-HT(3) receptors is likely to contribute to the M58996-induced antinociception.

Double-blind study on the effects of topical anesthesia on laryngeal secretions

The application of topical anesthesia to the oropharynx is a common clinical practice during oral and nasal laryngoscopy. Clinically, questions have been raised about whether topical anesthesia alters laryngeal secretions, which distorts clinical impressions. A double-blind, placebo controlled design was employed to address this issue. Ten premenopausal women with healthy vocal folds and 10 premenopausal women with phonotraumatic lesions underwent oral videolaryngoscopic examinations on subsequent days under both anesthesia and placebo conditions, in counterbalanced order. Video segments were rated by three judges. Dependent variables were balling and pooling of secretions, as previously described in the literature. Statistical analyses failed to reveal any clear effect of topical anesthesia on either secretion balling or pooling for the collapsed data set, but one cannot exclude changes in individual cases. Moreover, there was no evidence that secretions were differentially affected by anesthesia across subject groups. Null results in this data set replicate and extend previously reported findings by other authors. An incidental but potentially interesting finding was that the order of treatment condition (anesthesia versus placebo first) seemed relevant for secretions: Subjects who received the anesthesia condition first tended to show more secretion balling in general, as compared with subjects who received the placebo condition first. Speculation is entertained regarding possible physiological pathways for these incidental findings, which could be relevant for some clinical practice.

Tongue entrapment in an aluminum juice can

Tongue entrapment in bottles and cans is rare, but occurs. The following is a case report of a 10-year-old female who got her tongue entrapped in an aluminum juice can. The anatomy of the tongue, complications from injury, and a proposed removal procedure are described.

The need for caution with topical anesthesia during endoscopic procedures, as liberal use may result in methemoglobinemia

During upper gastrointestinal endoscopy, topical oropharyngeal anesthesia with lidocaine and/or benzocaine is used routinely by many endodscopists. Although such a practice is usually safe, there have been a number of reports of methemoglobinemia induced by topical anesthesia. Early treatment is extremely important as the development of methemoglobinemia is potentially fatal. Methemoglobinemia should be considered when oxygen desaturation occurs without another explanation. In this case series, we report 4 cases of methemoglobinemia that followed the liberal application of Cetacaine for ERCP. All patients recovered after appropriate treatment but these cases serve to highlight the potential problem, the importance of early recognition and treatment, and the most appropriate treatment options.

Inhibiting effect of beta-cyclodextrin on thymine dimerization photosensitized by para-aminobenzoic acid

Beta-cyclodextrin can act as an efficient inhibitor of the photosensitized dimerization of thymine by para-aminobenzoic acid (PABA) in aqueous solution. This can be explained by considering the formation of an inclusion complex between PABA and beta-cyclodextrin.

[Allergy to local anesthetics]

Suspected allergic reaction to local anesthetics is a frequently encountered problem. Although some reactions are proven to result from an allergic mechanism, many remain unexplained, raising various levels of risk depending on the type of hypersensitivity involved. Good clinical management of allergic reactions is now well standardized, allowing for proper identification of the causal agent in proven cases.

Methemoglobinemia induced by topical anesthesia: a case report and review

Topical anesthetic drugs are widely used by clinicians during hospital and outpatient procedures and are also available to the public in a variety of over-the-counter preparations. Although generally safe, they may cause potentially life-threatening methemoglobinemia. We describe a patient who developed repeated episodes of severe methemoglobinemia after administration of topical Cetacaine spray (a proprietary mixture of benzocaine, tetracaine, and butamben) employed for pharyngeal anesthesia before endotracheal intubation, and briefly review the etiology and pathophysiology of this disorder. Cautious interpretation of oxyhemoglobin saturation values obtained by pulse oximetry or estimated from arterial blood gas analysis is crucial lest the diagnosis of severe methemoglobinemia and the resulting hypoxemia are overlooked. If necessary, the condition is usually readily corrected by intravenous administration of methylene blue.

[Allergy to sunscreens]

Introduced in the 1930s, the sun filters (chemical screens) are very widely used as they are contained in photo-protective creams and in many other cosmetics. Allergy to sun filters seems to be rare in the general population (< 2%), but more frequent in populations which are suspected of photo-dermatosis (2 to 25%). It is composed of contact allergies, but also photo contact allergies in 45 to 85% of cases. Photo-biological exploration is comprised of application of photopatches and thus is necessary together with epidermotests. Crossed allergies, though rare, may be seen between filters, but also with substances that have a close chemical structure. Treatment such as prevention, if photo-protection is necessary, rest in discarding the causal filter and use of non-allergenic mineral screens.

The PABA story

The qualities of para-aminobenzoic acid (PABA) are discussed and an account is given of how it came to be the favourite sunscreen of the post World War II era. Slowly, however, dermatologists became aware that it was a fairly common sensitizer and that it tended to cross-sensitize with compounds of similar chemical structure both in contact with the skin and given as systemic drugs. Furthermore, continued exposure to chemicals of this type could lead to autoimmune responses especially systemic lupus erythematosus and dermatomyositis. Discussion of these complications from the use of PABA took place at two meetings of the Dermatological Association of Australia in 1964 and 1965, and played a part in the slow withdrawal of PABA from sunscreens.

Methemoglobinemia: an unusual complication of topical anesthesia

Allergic reactions tend to be easily recognized and treated, but methemoglobinemia is a rare, life-threatening complication of topical anesthesia of which our staff was unaware until recently. Team work prevented a patient fatality. Directives to alert the staff to suspect methemoglobinemia in patients who develop cyanosis and decreased oxygen saturation levels after administration of topical anesthesia despite administration of oxygen will prevent fatalities in the future.

Contact sensitization to sunscreens

BACKGROUND

Para aminobenzoic acid (PABA) derivatives and cinnamate are chemical sunscreens that protect against UVB (290 to 320 nm). They may occasionally produce contact and photocontact sensitization.

OBJECTIVE

To report a sensitization to octyl-dimethyl-PABA and photosensitization to 2-ethylhexyl-p-metossicinnamate in a 31-year-old man.

METHODS

A patient with a 3-year history of a relapsing dermatitis involving the face, neck, legs, and knees is reported. The eruption had recurred every summer after sunlight exposure. Patch tests with International Contact Dermatitis Research Group (IC-DRG) standard series and the photopatch series (Hermal-Trolab, Reinbek, Germany) using Finn chambers on Scanpor (Norgesplaster A/S, Oslo, Norway) were carried out.

RESULTS

We found a positive reaction to Balsam of Peru, fragrance mix, Escalol 507, and Parsol MCX (Hermal-Trolab, Reinbek, Germany). Photopatch test revealed a positive reaction only for Parsol MCX.

CONCLUSION

The incidence of allergic contact dermatitis to sunscreens is considered low. Recently sunscreens patch test concentrations have been increased from 2% to 10%. These higher percentages will probably permit the identification of more cases of sunscreens allergy in the near future.

Proteinase inhibitors and pemphigus vulgaris. An in vitro and in vivo study

The aim of this study was to determine the inhibitory effect of clinically usable proteinase inhibitors p-aminomethylbenzoic acid (PAMBA), and aprotinin on acantholysis in skin organ culture and in clinical trials with pemphigus patients. PAMBA added to the culture medium at a concentration of 1 mg/ml fully prevented the acantholysis, while Contrykal at 10 ATrE/ml reduced acantholysis. Subsequently, we treated 12 patients (groups 1) with PAMBA 100-200 mg daily for 7 to 26 days in combination with a moderate dose of corticosteroid (mean dose 36.1 mg prednisolone equivalent) or immunosuppressive drugs. A second group of 12 patients (group 2) were treated with a high dose of corticosteroid (mean 94.2 mg prednisolone equivalent) and immunosuppressive drugs. Evaluation was performed before treatment, after 3 weeks and on discharge using a clinical scoring system. The inclusion of PAMBA in the treatment protocol of group 1 resulted in active disease being brought under control with lower corticosteroid doses. As a result, fewer side effects were observed in group 1 than in group 2. In our opinion, protease inhibitors may be useful as adjuvant drugs in the combination therapy of pemphigus.

Photopatch test reactivity: effect of photoallergen concentration and UVA dosaging

We have studied the influence of variations in allergen concentration and UVA dosaging on the results of photopatch testing with the Scandinavian standard photopatch series in 29 patients with photocontact and/or contact allergy to 1 or several of the allergens in that series. Photocontact test reactions were more sensitive to allergen dilution than plain contact test reactions. Even dilution from the standard 5% to 2.5% significantly reduced para-aminobenzoic acid photocontact test reactions. Reducing the UVA dose from the standard 5 J/cm2 to 2.5 or 1 J/cm2 in 2 out of 5 cases turned a significant (++) reaction into a doubtful one (+). Increasing the standard UVA dose of 5 J/ cm2 to 20-40 J/cm2 turned a single + photocontact reaction to trichlorcarbanilide and a single 1 + plain contact reaction to chlorhexidine into ++ reactions. In the majority of cases, however, neither photocontact nor plain contact test reactions were augemented by UVA doses up to 80 J/cm2. We conclude that a UVA dose of 5 J/cm2 is sufficient for eliciting photocontact allergic test reactions, and that a reduction of either the UVA dose level or the standard allergen concentrations of the Scandinavian photopatch test guidelines may cause loss of significant photocontact test reactions in a proportion of the cases.

Sunscreen intolerance. Contact sensitization, photocontact sensitization, and irritancy of sunscreen agents

Reports of contact sensitization and photocontact sensitization induced by various sunscreening agents are reviewed. Current knowledge about the most often used sunscreening agents is summarized. The problems of cross-sensitization and sensitization in photodermatoses are discussed. Strategies for patch and photopatch testing, as well as immediate-type testing, are critically evaluated.

Photocontact allergy to oxybenzone: ten years of experience

Intolerance of sunscreen agents has often been reported in the literature. This mainly comprises photosensitization to sunscreens such as oxybenzone. The aims of this study were to establish the incidence of photocontact allergy to oxybenzone and its relationship with the use of other cosmetics. From 1982 to 1992 we performed photopatch tests on 283 patients with suspected photodermatosis. Forty-six patients (16%) had positive reactions: 61 positive photopatch tests and 9 positive patch tests. Photocontact allergy to sunscreens was divided into 2 main groups: 35 cases to oxybenzone and 17 cases to para-aminobenzoic acid and its derivatives. Among our 35 cases of photoallergy to oxybenzone, more than one third had photoallergy to a daily moisturizer that contained oxybenzone.

Comparison of aminobenzoate potassium and placebo in the treatment of scleroderma

OBJECTIVE

To determine the safety and efficacy of aminobenzoate potassium (KPAB) in treating the skin manifestations of scleroderma.

METHODS

Via a 48-week prospective, randomized, double blind, placebo controlled trial we compared the efficacy of KPAB 12 g/day with matching placebo. Outcome measures included skin mobility and thickening scores, patient and physician global assessments and, measurements of maximal oral aperture and hand range of motion.

RESULTS

Of 146 patients who entered the study, 76 (52%) completed. Demographics of the study population included age 49 +/- 13 years, 83% women, mean (range) disease duration was 104 (7-600) months. There were no differences in the demographics of the KPAB vs placebo nor the group that completed the study compared with the withdrawal group. There were no clinical or statistically significant differences between the KPAB and the placebo treated groups in any of the outcome measures. Subgroup analyses of skin mobility and skin thickening based on age, extent of disease, severity of disease, duration of disease and involved vs uninvolved skin were performed, but no differences were noted. The overall compliance to the medical regimen was > or = 75% in 93% of patients completing the study. Eighteen patients in the KPAB group and 6 placebo patients withdrew due to adverse drug reactions (ADR). The most common withdrawals for ADR were gastrointestinal intolerance and headaches. All ADR resolved following withdrawal of medication.

CONCLUSION

KPAB did not alter the skin changes of scleroderma in a group of patients with relatively longstanding stable disease. KPAB was reasonably well tolerated in this group of patients.

Contact allergy to sunscreen chemicals in photosensitivity dermatitis/actinic reticuloid syndrome (PD/AR) and polymorphic light eruption (PLE)

From 1989-1991, 214 patients (45 PD/AR, 54 PLE, 115 controls) were patch tested to a sunscreen series containing 9 constituents. 16/214 (7.5%) patients reacted to one or more sunscreens, with allergy being significantly more common in PD/AR patients (10/45 versus 2/54 PLE and 4/115 contact dermatitis clinic controls). The benzophenone group of sunscreens (mexenone, oxybenzone) were the most frequent sensitizers, accounting for 8 of the 27 positive patch tests observed. Clinicians should consider contact allergy to sunscreens in PD/AR patients as an explanation for exposed-site dermatitis episodes.

Drug-induced hair colour changes

Drug-induced hair colour changes are not a common adverse effect from medications. A wide variety of drugs have been implicated in causing hair colour changes but very few have data to support a true relationship. Of the drugs reported, chloroquine and cancer chemotherapeutic agents have the best evidence to support an association. Other drugs, such as p-aminobenzoic acid, calcium pantothenate, anthralin, chinoform, mephenesin, minoxidil, propofol, valproic acid, and verapamil await confirmatory data. Drug-induced causes should be considered in any patient with unexplained hair colour changes.

A three-year photopatch study in Thailand

Photopatch testing was performed on 274 patients who had history of photosensitivity at the Institute of Dermatology Thailand from 1987 through 1989. A total of 92 positive photocontact reactions and 71 positive contact reactions were seen. The most frequent positive photopatch test reactions were to sulfanilamide (18.2%) followed by Jadit (4.4%) chlorpromazine (3.6%) promethazine (3.6%) and fenticlor (3.2%). The most common photodermatoses was polymorphous light eruption (60.9%). Photocontact dermatitis was established in 28 patients (10.2%) while other skin diseases aggravated by sunlight were seen in 47 patients (17.2%).

Sunscreen. The ultimate cosmetic

There are sunscreens for every type of skin, activity, and personality. The physician should select a product for his patients intelligently, considering factors such as convenience, protection, sensitization, and comedogenicity.

[Anaphylactic shock after sucking on a throat lozenge]

A few minutes after sucking a lozenge for a sore throat a 68-year-old man developed an anaphylactic shock. At a heart rate of 110/min there was no palpable blood pressure. A red confluent exanthem, predominantly of the trunk, was noted. After brief intensive-care treatment the patient was completely well again and diagnostic tests for allergy were performed. The prick test for the 14 individual ingredients of the throat lozenge produced massive reddening and urticaria on the test arm with carbowax, a polyethylene glycol which serves as a vehicle in the remedy and does not have to be listed. Later there were an urge to cough and urticaria all over the trunk. There was no systemic reaction. Neither specific IgE antibodies nor any complement-consuming reaction could be demonstrated. Thus the precipitating mechanism remains unexplained.

Sunscreening agent intolerance: contact and photocontact sensitization and contact urticaria

Reports in the literature of sensitization associated with many commonly used sunscreening agents including p-aminobenzoic acid (PABA), PABA derivatives, anthranilates, salicylates, cinnamates, benzophenones, and dibenzoylmethane derivatives are reviewed. Several of these case reports involved subjects with various photodermatoses, implicating enhanced sensitivity of the patient's skin to both light and chemicals. Despite the widespread use of sunscreens, the small number of published reports of contact and photocontact sensitization to these agents suggests that either such sensitization is less than commonly perceived or is underreported. Establishment of a registry for reporting adverse effects associated with sunscreening agents would help to characterize the incidence of sensitization.

Photoallergy to benzophenone

Incorrect diagnosis of photoallergy to sunscreen products represents a unique clinical dilemma. Increasing sunscreen usage for suspected idiopathic photosensitivity or a change to a sunscreen containing the same photoallergen only worsens the problem. While photoallergy to p-aminobenzoic acid and its esters is well known by dermatologists and the lay public, benzophenone photoallergy is not well appreciated. We report herein the cases of four individuals with photoallergy to oxybenzone in sunscreens. It is likely that such reactions will become more commonplace since oxybenzone is by far the most frequently used agent in modern, high sun protection factor sunscreens (greater than 8 sun protection factor) being marketed today.

Contact photoallergy testing of sunscreens in guinea pigs

The potential of 3 sunscreens (p-aminobenzoic acid, 4-isopropyldibenzoylmethane and homosalate) and 2 known human photoallergens (musk ambrette and tetrachlorosalicylanilide) to cause photoallergy, phototoxicity, and/or contact sensitization was determined using a guinea pig photoallergy model, as previously described by Harber and associates. The model was slightly modified by employing 6 exposures over 2 weeks and using Hill Top Chambers for application of the test material. Contact photoallergy was detected in guinea pigs treated with musk ambrette or tetrachlorosalicylanilide (TCSA), although with TCSA, a lower incidence of contact sensitivity and phototoxicity was also detected. The results of studies conducted with sunscreens showed that p-aminobenzoic acid was photoallergenic, whereas homosalate and 4-isopropyl-dibenzoylmethane (Eusolex 8020) were not. However, contact sensitization, and to a lesser degree primary irritation, was detected with Eusolex 8020 at the concentrations employed in this study. The results of these studies suggest that this guinea pig model is a suitable model for assessing the photoallergic potential of various compounds, including the sunscreens tested in this study.

Contact and photocontact allergy to glyceryl para-aminobenzoate

High-purity glyceryl para-aminobenzoate was produced from a commercial source of the chemical by using a chromatographic technique. Negative test reactions to this purified substance were obtained when it was patch/photopatch-tested on 2 patients with contact and photocontact allergy to a nonpurified batch of glyceryl para-aminobenzoate.

Persistent light reaction: induction in the guinea pig

Persistent light reactions similar to those in humans were observed in the study of photoallergenicity of chemicals in guinea pigs. The animals photoinduced with chemicals reacted to long-wavelength ultraviolet (UVA) radiation in the absence of test materials at the challenge stage. The sensitivity of the animals to UVA persisted for more than 1 year. The minimum erythema dose to UVB of animals in the treated group was less than that in the control group. Our investigations indicate that the main factors influencing the elicitation of persistent light reaction were the amount of Freund's complete adjuvant (FCA) used to enhance the allergic response in animals, and the UVA dose at the induction stage. Based on these findings, we have developed a method to make animals persistent light reactors with high frequency. This method consists of 1 intradermal injection of 1.2 ml emulsified FCA, 5 irradiations with 20.4 J/cm2 of UVA, and topical applications of 5% p-aminoethylbenzoate (benzocaine) at the induction stage. We also found that photosensitivity could be induced using FCA and UVA without photosensitizers.

Potassium para-aminobenzoate and liver function test findings

Risk of hepatotoxicity has been raised with respect to potassium para-aminobenzoate (Potaba) therapy. In this regard relevant clinical and laboratory hepatic findings in the hospital records of 390 scleroderma patients were analyzed. There were 274 patients who had received potassium para-aminobenzoate at some time and 116 who never received it. No instance was found in which potassium para-aminobenzoate was the cause of an acute hepatic hypersensitivity reaction. There were random or intercurrent abnormalities in hepatic test findings over time, but these actually occurred more often in the group of patients never treated with potassium para-aminobenzoate. Further, there was no evidence that long-term potassium para-aminobenzoate therapy is hepatotoxic. These findings suggest that acute hepatic reaction to potassium para-aminobenzoate is at least uncommon if not rare.

Sunscreens. Topical and systemic approaches for the prevention of acute and chronic sun-induced skin reactions

In this article, practical and clinical aspects of photoprotection are discussed with emphasis on topical sunscreens. Protection against the adverse effects of sunlight includes prevention of the following: sunburn in normal individuals; acute phototoxic and photoallergic reactions; chronic skin damage (dermatoheliosis) and skin cancer; and specific disease-oriented responses (such as porphyria or polymorphous photodermatitis).

Infantile methemoglobinemia induced by a topical anesthetic, Cetacaine

A 2-month-old infant developed severe methemoglobinemia following topical pharyngeal application of a common benzocaine containing agent ( Cetacaine ). Although a number of reports of this complication have appeared in recent years, this is apparently the first case reported in the Otolaryngology literature. The pathophysiology, pharmacology, and treatment of this condition are reviewed.