Sap and Sun: A Case of Phytophotodermatitis

We report a case of phytophotodermatitis caused by cow parsnip (Heracleum maximum) exposure affecting a hiker in Colorado. Phytophotodermatitis is a phototoxic skin reaction to UV-A rays after contact with photosensitizing plant substances that presents as a burning, painful rash, often with blisters. Treatment is supportive, including wound hygiene, analgesia, and anti-inflammatories. Avoiding offending plants, protecting the skin from sun, and immediate washing with soap and water after plant contact are the primary means of prevention. We have included a table and photos of plants found in the United States that can cause phytophotodermatitis. Medical providers should include phytophotodermatitis in the differential diagnosis of blistering rashes in patients who have been outdoors with possible exposure to offending plants.

[Current problems of polypharmacy in geriatric patients when taking drugs with a risk of photosensitivity.]

The article presents an overview of the current problems of polypharmacy in geriatric patients when taking drugs with a risk of photosensitivity. The article contains information about emerging adverse drug reactions, as well as methods for diagnosing, correcting and preventing phototoxic and photoallergic reactions in patients of older age groups. The main aspects of dermatological support in the system of long-term care for geriatric patients when taking drugs with a risk of photosensitivity are outlined. Clinical signs of senile xerosis and skin manifestations of adverse drug reactions were studied when taking drugs with the risk of photosensitization before and after the use of a photoprotector in elderly patients.

Improper Use of the Germicidal Range Ultraviolet Lamp for Household Disinfection Leading to Phototoxicity in COVID-19 Suspects

PURPOSE

To report the germicidal range ultraviolet (UV) irradiation-induced phototoxicity because of unprotected exposure to the UV lamps for presumed household disinfection of SARS-CoV-2 in a domestic setting.

METHODS

We report on a family of 3 adults who experienced photophobia, intense eye pain, epiphora, blurred vision, and a burning sensation over the face and neck area after a short period of unprotected exposure to the UV germicidal lamps.

RESULTS

An initial examination revealed erythema and tenderness over the face and neck area, reduced visual acuity of 6/12, and conjunctival injections bilaterally in all 3 patients. Further assessment at the ophthalmology department 3 days later revealed gradual improvement of visual acuity to 6/6 bilaterally. Slit-lamp examinations revealed few punctate epithelial erosions. Fundal examinations were normal without evidence of solar retinopathy. The patients were diagnosed with germicidal range UV irradiation-induced photokeratitis and epidermal phototoxicity. Lubricants and emollients were prescribed for symptom relief, and the patients were warned against using a UV germicidal lamp for disinfection purposes without appropriate protection.

CONCLUSIONS

Although SARS-CoV-2 is structurally akin to SARS-CoV-1 and MERS-CoV, and previous studies demonstrated high levels of inactivation of beta-coronavirus with germicidal-range UV, evidence for its efficacy to inactivate SARS-CoV-2 is lacking. This case report serves to emphasize the potential consequences of phototoxicity from the improper use of UV germicidal lamps for household disinfection and to highlight the fact that UV germicidal lamps currently have no established role in household disinfection of SARS-CoV-2.

Lesson of the month 2: An unusual adverse reaction associated with pramipexole

Dopamine agonists such as pramipexole are commonly used in the treatment of restless legs syndrome (RLS) as well as Parkinson's disease. Pramipexole's common side effects are well documented; however, adverse skin reactions are less well known. In this case, a 45-year-old male farmer presented with excessive daytime tiredness and reported a history suggestive of RLS. He was initiated on pramipexole but developed a maculopapular erythematous rash in sun-exposed areas 8 days after its commencement. The skin rash resolved following pramipexole's cessation and it is thought the patient experienced a drug-induced photosensitivity reaction to pramipexole. This case highlights the potential for photosensitivity reactions to pramipexole, which is especially significant in countries like Australia where UV solar radiation is especially high.

Exploration of alternative test methods to evaluate phototoxicity of ophthalmic agents by using Statens Seruminstitut Rabbit Cornea cell lines and 3D human reconstituted cornea models

Many chemicals have been reported to induce phototoxicity. The absorbance of light energy within the sunlight range is a common characteristic of phototoxicity. The 3T3 NRU phototoxicity test (PT) in 3T3 mouse skin fibroblasts has been used to identify the phototoxic potential induced by excited chemicals after exposure to ultra violet (UV). However, as phototoxicity may occur in ocular cells, it is necessary to develop a more suitable test for cornea-derived cells. In this study, we attempted to establish a new in vitro PT method in rabbit corneal cell lines (SIRC). We evaluated five ophthalmic agents, ciprofloxacin, levofloxacin, lomefloxacin, norfloxacin, and tetracycline, for their cytotoxic potential and in vitro phototoxicity. The results obtained using 3D human corneal models revealed that the UV-induced eye tissue toxicity by the test substances showed good correlation with those obtained using the in vitro phototoxicity test. However, the results from the 3D PT for ciprofloxacin, norfloxacin, and tetracycline in the 3D human cornea model were only partially comparable. Therefore, we suggest the SIRC cell line as a new phototoxicity test model; however, a sequential testing strategy, such as 3D PT, was also proposed to obtain relevant information for topical eye agents.

Phytophotodermatitis related to carrot extract-containing sunscreen

Phytophotodermatitis is a clinical diagnosis from phototoxicity of the skin induced by contact with plants or their extracts. Phytophotodermatitis maypresent with burning, erythema, patches, plaques, vesicles, bullae, or hyperpigmented patches in welldemarcated and unusual shapes. Inquiring about occupation, hobbies, and plant or plant extract contact is essential to establishing the diagnosis. Herein we present a case of phytophotodermatitisafter use of carrot extract-containing sunscreen presenting as a hyperpigmented patch in a geometric distribution with accentuation of pigment within the dynamic rhytides.

Evaluation of chemical phototoxicity, focusing on phosphorylated histone H2AX

Histone H2AX is a minor component of nuclear histone H2A. The phosphorylation of histone H2AX at Ser 139, termed γ-H2AX, was originally identified as an early event after the direct formation of DNA double-strand breaks (DSBs) by ionizing radiation. Now, the generation of γ-H2AX is also considered to occur in association with secondarily formed DSBs by cellular processing such as DNA replication and repair at the site of the initial damage, including DNA adducts, crosslinks, and UV-induced photolesions. Therefore, γ-H2AX is currently attracting attention as a new biomarker for detecting various genotoxic insults. We have determined the toxic impact of various environmental stresses such as chemicals, light and/or their coexposure using γ-H2AX, and found that the γ-H2AX assay exhibited high sensitivity and a low false-positive rate as a detection system of genotoxic potential. In this review, we introduced our recent findings concerning the evaluation of chemical phototoxicity, focusing on γ-H2AX.

Phytophotodermatitis

Phytophotodermatitis is a phototoxic cutaneous eruption due to skin exposure to furocourmarins combined with ultraviolet light. Bizzare linear patterns, ranging from erythema to bullae with residual hyperpigmentaion, is the clinical clue to this diagnosis. Avoidance of furocoumarins in direct sunlight can prevent recurrences.

Ocular cells and light: harmony or conflict?

Vision is based on the sensitivity of the eye to visible rays of the solar spectrum, which allows the recording and transfer of visual information by photoelectric reaction. Any electromagnetic radiation, if sufficiently intense, may cause damages in living tissues. In a changing environment, the aim of this paper is to point out the impact of light radiation on ocular cells, with its phototoxicity potential on eye tissues. In fact, faced with light and oxygen, the eye behaves like an ephemeral aggregate of unstable molecules, like a temporary crystallization threatened with entropia.

Photoallergic reaction to cyamemazine

A 50-year-old man presented with a scaly erythema of the face, upper chest, forearms, and dorsum of the hands. He has been treated with cyamemazine for 6 months. Photopatch tests were performed and the patient was diagnosed with photoallergic reaction to cyamemazine. The drug was discontinued and a course of oral steroids was prescribed. The patient was advised to avoid light exposure. There has been no evidence of recurrence during a six-month follow-up period. Photoallergic reactions are much less frequent than phototoxic disorders. It is well known that several drugs including neuroleptics of the phenothiazine family may produce a skin eruption on light-exposed areas by dose-dependent (phototoxic) or photoallergic mechanisms. It is believed that photopatch testing, which is the clinical investigation of choice for suspected photoallergic reactions, is significantly underused in Europe and probably world-wide.

Phototoxic and photoallergic cutaneous drug reactions

A variety of topical and systemic drugs can induce cutaneous photosensitive reactions. These drugs and their metabolites accumulate in the skin and increase photosensitivity of the skin typically in the UVA spectrum of light. Concerning the underlying biochemical mechanisms and the phenotype of reactions, photosensitivity can be divided into phototoxic and photoallergic reactions. In phototoxic reactions, often highly reactive oxygen molecules are formed that induce tissue damage. Skin changes resemble sunburn and develop within hours after incubation with the drug together with sunlight. In contrast, photoallergic reactions are type IV hypersensitivity reactions, and therefore resemble eczema. They usually develop within days and are less common than phototoxic reactions. Diagnosis is based on a synopsis of complete history, clinical examination, phototesting for minimal phototoxicity dose, patch testing including photopatch tests, and histopathology. Mainstays of treatment are the withdrawal of the culprit drug, and avoidance of sunlight by wearing protective clothing and broadband sunscreens with UVA filters.

Phototoxicity of oriental medicinal plants: measurement and possible applications

Phototoxicity can be either harmful and induce adverse skin reactions or beneficial and be used therapeutically as in psoralen and UV-A or photodynamic therapy. Hundreds of medicinal plants are widely used in Asia and Western countries in oriental medicine, yet the phototoxicity of oriental medicinal plants is an understudied area. In this contribution, the authors discuss some methods used to measure the phototoxicity of plants and give an overview of the results of their previous and ongoing studies into the phototoxicity of medicinal plants. The authors argue that because they found that more than a quarter of oriental medicinal plants can be phototoxic, such research is helpful for dermatologists and that active phototoxic components extracted from oriental medicinal plants may be used therapeutically.

Professional photosensitive eczema of fishermen by contact with bryozoans: disabling occupational dermatosis

Eczema associated with bryozoans is a form of occupational dermatosis caused by a living animal, involving contact eczema, occasionally associated with photosensitivity and concerning fishermen on a quasi-elective basis. This affection can prove to be extremely disabling, frequently generating disastrous social consequences, since the eviction of the responsible allergen is very often synonymous to occupational reclassification, a measure which fishermen, highly attached to their profession, have great difficulty in accepting. Based on the description of three cases of photosensitive eczema associated with contact with the bryozoan, Alcyonidium gelatinosum, identified in fishermen from the English Channel coastline, we describe the characteristics and the specificities of this occupational dermatosis, then approach the issue of its prevention, which, unfortunately, remains limited.

Dapsone induced acute photosensitivity dermatitis; a case report and review of literature

Dapsone is one of the main constituents of anti-leprosy treatment and has been in use for various dermatological and non-dermatological indications since the 1940s. Dapsone-induced photosensitivity is a rare complication. Only 11 cases seem to have been reported in the literature. We report a case of dapsone-induced photosensitivity in an Indian patient with leprosy, and briefly review the literature. Dapsone (diaminodiphenyl sulphone or DDS) is the most commonly used anti-leprosy drug since the 1940s. Apart from leprosy, it is used for various other infectious and non- infectious dermatoses as well as for prevention of Pneumocystis carinii pneumonia in HIV infected patients. It is one of the main constituents of multidrug therapy (MDT) in leprosy by virtue of its anti-mycobacterial properties. It acts by interference with folate metabolism. Because of its inhibitory effect in neutrophil chemotaxis and neutrophilic oxygen burst, it acts as a potent anti-inflammatory agent. Documented cutaneous adverse effects of dapsone include generalised maculopapular rash, exfoliative dermatitis, toxic epidermal necrolysis, erythema multiforme, erythema nodosum, pustular and acneiform skin eruptions. Photosensitivity dermatitis is a very rare side-effect of dapsone and to the best of our knowledge, only 11 cases have been reported in the literature to date.

Herb of Grace: An Unusual Cause of Phytophotodermatitis Mimicking Burn Injury

We report the case of a 2-year-old child who suffered an acute phytophotodermatitis with systemic upset after contact with the herb Ruta Graveolens (common rue, Herb of Grace). We review the literature detailing the mechanism of the phytophotodermatitis and the mainstream and alternative medicinal uses of the herb. Clinicians treating burns should consider phytophotodermatitis in their differential diagnosis of any partial-thickness burn injury. Furthermore, the hazards of growing this widespread herb in gardens where children play should be well publicized.

Heracleum mantegazzianum and Toxicodendron succedaneum: plants of human health significance in New Zealand and the National Pest Plant Accord

New Zealand's National Pest Plant Accord (NPPA) is a voluntary and cooperative agreement between industry, regional councils, and central government departments with biosecurity responsibilities (primarily the Ministry of Agriculture and Forestry and the Department of Conservation). Plant species included in the NPPA are declared unwanted organisms under the Biosecurity Act 1993, which prevents their sale, propagation, or distribution across the country. Although MAF Biosecurity New Zealand (the lead agency in New Zealand's biosecurity system) has evaluated the potential human health impacts of 202 species considered for inclusion in the NPPA, two species were examined primarily due to their significance to human health: Heracleum mantegazzianum (giant hogweed, cow parsnip, wild parsnip) and Toxicodendron succedaneum (rhus tree, wax tree, Japanese wax tree). As a result of this process, H. mantegazzianum has been listed in the NPPA. In contrast, T. succedaneum was not included in the NPPA, as the latter was deemed to be an inappropriate mechanism for its control. In this article the NPPA process is outlined, and the adverse impacts on human health of these two species are discussed--including symptoms, treatment, and possible management measures.

Drug-induced photoallergic and phototoxic reactions

Drug-induced photosensitivity involves reactions to medication triggered by exposure of the skin to ultraviolet light. Medications that trigger reactions can be topical or oral. Following interaction of ultraviolet radiation with a chemical present in sufficient amounts in the skin, one of the several reactions may occur in susceptible patients, most commonly photoallergy or phototoxicity. These reactions can be diagnosed separately based on pathogenesis, clinical characteristics and histopathology. Phototoxic disorders have a higher incidence than photoallergic disorders. The action spectra for most photoallergens and phototoxins lie in the ultraviolet A range. Subtypes of drug-induced photosensitivity include dyschromia, pseudoporphyria, photo onycholysis, and lichenoid and telangiectatic reactions.

Rue the Herb: Ruta graveolens-Associated Phytophototoxicity

We describe an unusual case of phytophototoxicity induced by an herbal plant, Ruta graveolens, from the Rutaceae family. This common herb, also called rue, can be found throughout rural settings in the United States. When psoralens from rue come in contact with human skin that is subsequently exposed to ultraviolet A light, an impressive photoirritant reaction can occur. This report both clarifies the distinguishing features of photoirritant reactions versus photoallergic reactions and reviews the pathophysiology and clinical presentation of phytophotodermatitis. R. graveolens can be associated with an impressive photoirritant reaction and should not be used as an insect repellent.

[Purely natural: phototoxic dermatitis]

The local application of undiluted bergamot oil in association with simultaneous exposure to sunlight brought about a phototoxic reaction of the skin. Despite successful treatment of the vesicles, Hyperpigmentation and stress-related erythema persisted.

Phototoxic and photoallergic skin reactions

Indirect action of sun together with different exogenous agents (systemic medications and topically applied compounds) sometimes may result in phototoxicic and photoallergic reactions. Drug-induced photosensitivity reactions refer to the development of cutaneous disease as a result of the combined effects of a drug and light (mostly spectrum within the UVA and visible light range or UVB range). The aim of the review was to show the prominent features of phototoxic and photoallergic reactions, which occur in sun-exposed areas, including face, neck, hands and forearms. Phototoxic reactions are significantly more common than photoallergic reactions and mostly resemble to exaggerated sunburn. Photoallergic reactions appear only in a minority of individuals and resemble allergic contact dermatitis on sun-exposed areas, although sometimes may extend into covered areas. Generally, the physical examination and a positive patient's history of photosensitivity reactions on substances are of great importance for the diagnostics. The treatment of these reactions includes identification and avoidance of offending agent and application of anti-inflammatory dressings, ointments and corticosteroids.

The many faces of phytophotodermatitis

Phytophotodermatitis is a common cutaneous phototoxic reaction produced by contact with a variety of plant substances, followed by sunlight exposure. Phytophotodermatits can simulate child abuse, impetigo, superficial lymphangitis, and larva migrans. The most frequent presentation is hyperpigmentation of the dorsum of the hands, but there are other less common findings such as blisters or lesions mimicking solar lentigines and melasma.

[Eczematous skin diseases]

The skin, as one of the most important barriers of the human body, protects the inner homeostasis from the harmful environmental influences as well as physical, chemical and biological factors. When the impact of these factors exceeds the tolerance and reproducing capacity of the skin, pathological alterations will develop. If follows from this that dermatology can surely be considered to be a part of environmental medicine. Eczematous diseases are mostly pathological pictures of varied mechanisms developing as a result of environmental influences (irritants, contact allergens, microbes). Since their clinical appearance is similar, it is a serious professional challenge to diagnose them. In this article we present the clinical features, provoking factors of these skin diseases as well as therapeutical possibilities.

Assessing phytophotodermatitis: boy with erythema and blisters on both hands

Phytophotodermatitis (PPD) is a phototoxic reaction which occurs when the skin comes in contact with a photosensitizer and is subsequently exposed to radiation. PPD is often seen in people handling furocoumarin-containing products, such as agricultural workers, bartenders, florists, and gardeners. It may also be seen in beachgoers, athletes, and children. The pattern of the lesions usually resembles streaks; the hands and mouth are most commonly affected due to eating and handling of the offending furocoumarin-containing agents.

Thioridazine Induces Immediate and Delayed Erythema in Photopatch Test

Thioridazine is a phenothiazine derivative that has been used as an antipsychotic; it rarely causes photosensitization. However, we noticed that this drug induced an erythematous reaction in a photopatch test. Six volunteers were patch tested with various concentrations of thioridazine and irradiated with a range of UVA doses, and the time courses of the color of and blood flow to the test sites were monitored. The free-radical metabolites of thioridazine generated under UVA irradiation and its effects on ascorbate radical formation were examined with an electron paramagnetic resonance (EPR) spectrometer in vitro. As a result, immediate erythema developed during UVA irradiation in most subjects when 1% thioridazine was applied for 48 h and irradiation doses were higher than 4 J cm(-2). Another peak of erythematous reaction was observed 8-12 h after irradiation. The in vitro examination detected an apparent EPR signal, which appeared when 2 mM thioridazine in air-saturated phosphate buffer was irradiated with UVA, whereas this reaction was attenuated under anaerobic conditions. The EPR signal of the ascorbate radical was augmented under both aerobic and anaerobic conditions. Thioridazine-derived oxidants and/or thioridazine radicals generated during UVA irradiation seem to play an important role in this unique phototoxic reaction.

Scientific problems of photosensitivity

Photosensitive skin reactions occur when human skin reacts to ultraviolet radiation or visible light abnormally. The forms of photosensitivity are phototoxicity and photoallergy. Phototoxic disorders have a high incidence, whereas photoallergic reactions are much less frequent in human population. Several hundred substances, chemicals, or drugs may invoke phototoxic and photoallergic reactions. In order to avoid photosensitive reactions it is essential to determine the photosensitizing properties of such substances before drugs are introduced in therapy or products made available on the market. The article reviews the mechanisms of photosensitization, explains the most important differences between phototoxic and photoallergic reactions, summarizes the most common photosensitizers, and presents the clinical features and diagnostic procedures of phototoxic and photoallergic reactions.

[Toxic mustard plaster dematitis and phototoxic dematitis after application of bergamot oil]

Two cases that illustrate the risks attendant on the therapeutic use of natural medications by laypersons are reported. In the first case, the application of a mustard plaster triggered toxic dermatitis. In the second case, a session in a solarium after the external application of bergamot oil resulted in a phototoxic reaction.

The human epidermis models EpiSkin, SkinEthic and EpiDerm: an evaluation of morphology and their suitability for testing phototoxicity, irritancy, corrosivity, and substance transport

The commercially available reconstructed human epidermis models EpiSkin, SkinEthic and EpiDerm demonstrate reasonable similarities to the native human tissue in terms of morphology, lipid composition and biochemical markers. These models have been identified as useful tools for the testing of phototoxicity, corrosivity and irritancy, and test protocols have been developed for such applications. For acceptance of these tests by the authorities, prevalidation or validation studies are currently in progress. Furthermore, first results also indicate their suitability for transport experiments of drugs and other xenobiotics across skin. Still, however, the barrier function of these reconstructed human epidermis models appears to be much less developed compared to native skin. Further adaptation of the models to the human epidermis, especially concerning the barrier function, therefore remains an important challenge in this area of research.

Photosensitivity to Exogenous Agents

OBJECTIVE

To better understand cutaneous photosensitivity reactions, a review of its etiologic factors, clinical characteristics, pathogenesis, and treatment modalities was undertaken.

METHODS

Articles discussing the above aspects of phototoxic and photoallergic reactions were used to demonstrate what is currently known about photoinduced reactions and how to treat them.

RESULTS

Upon interaction of solar UV radiation with the chemical that is present in significant levels on the skin, one of two known reactions may occur in susceptible patients: a phototoxicity and/or photoallergy. Phototoxic and photoallergic reactions can be diagnosed separately on the basis of pathogenesis, clinical characteristics, and histology. Examples of drugs capable of inducing a phototoxic reaction include amiodarone, retinoids, nonsteroidal antiinflammatory agents, diuretics, and antibiotics. Substances known to cause a photoallergic response are fragrances, sunscreens, topical antimicrobials, NSAID, and psychiatric medications, such as chlorpromezine.

CONCLUSION

Photoinduced reactions produced by exogenous chemicals are common skin disorders. Definitive therapy requires identifying and removing the offending agent, either the photosensitizing chemical or light. The use of fully protective clothing and a sunscreen of high SPF are important measures when light exposure is inevitable.

Phototoxic dermatitis due to Chenopodium album in a mother and son

Chenopodium album L. subs. album (Chenopodiaceae) is an annual herb with fibrous roots. The plant grows worldwide and frequently in moist areas. Sometimes, the young parts of this plant can be cooked and eaten as a vegetable. In this article, we report a mother and her adult son, in whom phototoxic reaction developed on the sun-exposed body areas after eating this plant of Chenopodiaceae family because of rare presentation. We thought that this reaction was probably due to furocoumarins constituent within the plant.

Phototoxic reaction to xanthene dyes induced by visible light

Many dyes, for instance methylene blue, rose bengal, and eosin, are known as photosensitizers, and in the presence of molecular oxygen they induce cell lethality and skin photosensitivity (1-4). Several dyes are used in cosmetic products, particularly in lipsticks. Human lip skin is therefore exposed to potential danger from dye-sensitized phototoxic reactions. Using an in vivo system of mammalian skin, such as the abdominal skin of rabbits, we established screening tests for the phototoxic potential of synthetic dyes in two ways: (a) intracutaneous injection; (b) topical application with and without damaging the barrier property of the stratum corneum. In the intracutaneous injection assay, distinct phototoxic reactions were induced by rose bengal, eosin Y.S., and dibromofluorescein. When these dyes were applied topically to intact skin, no phototoxic reactions were observed. Phototoxic reactions were, however, elicited when the dye solutions were applied to abraded or scratched skin. The intensity of phototoxic reaction was found to be influenced by the vehicle in which the dyes were suspended. Phototoxic reaction to the dyes was induced by artificial light as well as by sunlight. By using commercially available fluorescent lamps with different spectral emissions, the action spectra for the phototoxic reaction to these dyes were investigated and it was found that the maximum phototoxicities of the dyes were manifested by light within a spectral range of 400-600 nm. Further studies on action spectra, using a monochromatic irradiation system, revealed a high correlation between the action spectra of the dyes and their absorption spectra. Maximum effective wavelength for the phototoxic reaction of eosin Y.S. was 525 nm. This topical as well as intradermal assay for assesing phototoxic reaction to synthetic dyes in living skin will be a practical and useful measure for studying the phototoxicity of the dyes.

Photocontact dermatitis

Photocontact dermatitis is not a common condition, but neither is it rare. Both photo-irritant contact dermatitis (PICD) and photoallergic contact dermatitis (PACD) are seen by most dermatologists in general practice. PICD is diagnosed on clinical grounds and is usually caused by furocoumarins in plants like limes and celery. PACD is caused primarily by sunscreens but can also be the result of fragrances and antibacterial agents. PACD can only be diagnosed by photo-patch testing that most dermatologists, even those who patch test and give phototherapy in their office, do not perform. The procedure as outlined in this manuscript is relatively simple and can easily be accomplished in the dermatologist's office.

Dacarbazine but not temozolomide induces phototoxic dermatitis in patients with malignant melanoma

Ten patients with malignant melanoma and phototoxic reactions under dacarbazine or 5-(3,3-dimethyl-1-triazeno) imidazole-4-carboxamide (DTIC) chemotherapy were investigated. All patients available for testing showed increased ultraviolet A-sensitivity (n = 5); patch testing revealed no type IV allergies (n = 6). In 5 patients intravenous DTIC was replaced by oral temozolomide, and no phototoxicity occurred. Temozolomide may represent an alternative for patients with DTIC-induced phototoxic skin reactions.

Common hyperpigmentation disorders in adults: Part I. Diagnostic approach, café au lait macules, diffuse hyperpigmentation, sun exposure, and phototoxic reactions

The cause of hyperpigmentation usually is traced to the activity and presence of melanocytes. Café au lait macules may be solitary benign findings or may indicate the presence of neurofibromatosis with its associated complications. Diffuse hyperpigmentation should prompt a search for offending medications or systemic diseases such as hemochromatosis, hyperthyroidism, and Addison's disease. In these instances, the hyperpigmentation may be ameliorated by discontinuing offending medications, performing serial phlebotomy in patients with hemochromatosis, instituting cause-specific treatments in patients with hyperthyroidism, and replacing deficient glucocorticoids and mineralocorticoids in patients with Addison's disease. Cosmetic treatment with bleaching agents or lasers can be used to decrease pigmentation of ephelides (freckles) and lentigines.