Author's personal copy Travel Medicine and Infectious Disease (2013) 11, 337e349 Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevierhealth.com/journals/tmid INVITED SUBMISSION Not to be missed! Differential diagnoses of common dermatological problems in returning travellers Andreas Neumayr a,b, Christoph Hatz a,b, Johannes Blum a,b,* a Swiss Tropical and Public Health Institute, Socinstrasse. 57, 4051 Basel, Switzerland b University of Basel, Basel, Switzerland Received 13 June 2013; received in revised form 20 September 2013; accepted 25 September 2013 Available online 6 October 2013 KEYWORDS Summary After systemic febrile illnesses and diarrhoea, dermatological disorders are the Travel; third most frequent health problem of returning travellers consulting travel clinics. While most Skin; travel-related dermatological problems are mild, self-limiting and rather harmless, the chal- Creeping eruption; lenge is to pick up on dermatological clues to potentially severe or even life-threatening dis- Chancre; eases. This article provides an overview of the most common and the ‘not to be missed’ Eschar dermatological diagnoses in international travellers. ª 2013 Elsevier Ltd. All rights reserved. Introduction dermatological diagnoses in travellers is broad and domi- nated by insect bites, bacterial skin infections, creeping The three most common reasons for returning travellers to eruptions and allergic skin reactions (Table 1). seek medical help are systemic febrile illnesses, acute or This article addresses the most frequent dermatological chronic diarrhoea and dermatological disorders [1]. Various disorders and their differential diagnoses in returning studies have recently reviewed the spectrum and the fre- travellers, and highlights the dermatological clues to severe quencies of travel-related dermatological disorders and potentially life-threatening diseases, which should not observed in travel clinics [1e4]. The spectrum of be missed: ‘When you hear hoofbeats, think horses, not zebras’. but make sure not to miss out on zebras. (Those dermatological disorders that are not confined to d * Corresponding author. Swiss Tropical and Public Health Insti- travelling e.g. herpes zoster, pityriasis rosea, syphilis d tute, Socinstrasse. 57, 4051 Basel, Switzerland. Tel.: þ41 61 284 and sun- and heat-related skin pathologies also 8111; fax: þ41 61 284 8101. frequently occur in travellers, but are beyond the scope of E-mail address: [email protected] (J. Blum). this review). 1477-8939/$ - see front matter ª 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.tmaid.2013.09.005 Author's personal copy 338 A. Neumayr et al. Table 1 Spectrum and frequency of travel-related dermatological disorders. Setting Herbinger 2011 Lederman 2008 Ansart 2007 Freedman 2006 Travel clinic in GeoSentinel Travel clinic in GeoSentinel Munich, Germany surveillance network Paris, France surveillance network (1997e2006) (1996e2004) Number of cases (n Z 4158) % (n Z 4594)% (n Z 165)% (n Z 2947) % Ectoparasites Arthropod/insect bite 16.8 8.2 9.7 18.7 Scabies 2.3 e 10 2.2 Myiasis 0.8 e 7.2 3.5 Tungiasis 0.6 e 4 e Tick bites 0.6 eee Bacteria Bacterial skin infectionsa 21.6 14.5 21.2 12.4 Rickettsial disease 1.3 e 0.6 e Leprosy ee 2.4 e Helminths Larva cutanea migrans 7.9 9.8 4.8 12.9 Schistosomiasis 0.6 e 0.6 e Filariasis (Loiasis) 0.7 e 5.5 e Gnathostomiasis ee 1.8 e Protozoa Cutaneous leishmaniasis 2.4 3.3 e 3.8 Virus infection 5.7 3.4 7.2 e Fungal infection 4.0 4.0 6.1 5.6 Allergic reaction/urticaria 5.4 5.5 4.8 11.3 Phototoxic 0.8 eee Chemical, toxic 0.5 e 3.6 e Injuries 1 eee Terrestrial animal bites 0.4 4.3 e >4.7 Maritime animals 0.7 eee Pruritus of unknown origin ee 9.1 e Unknown skin disorder 16.3 5.5 e 6.6 a including skin abscesses, impetigo, erysipelas, superinfected insect bites, etc. Methods picture may include ecchymoses or vesicles and severely allergic patients may develop haemorrhagic bullae, necroses This review is based on the most frequently reported skin or ulcers that heal with residual scarring [7]. In a few cases, pathologies in travellers (see Table 1), on the relevant insect bites may cause systemic symptoms like generalised literature and on personal experiences from daily practice urticaria, angioedema, anaphylaxis or the rare ‘Skeeter at our travel clinic. syndrome’ (a large local inflammatory reaction accompa- nied by fever, which can be differentiated from cellulitis by its peracute onset within hours) [8e10]. Sequelae of insect Ectoparasites bites include bacterial superinfection, post-inflammatory changes in pigmentation, prurigo simplex-like lesions, pru- Insect bites rigo nodularis and atrophic scarring [5,7]. Diagnosis Consultations for insect bites are frequent and the clinical Diagnosis is based on the patient’s history and clinical presentations vary widely. One insect may cause different picture. types of skin lesions and each type of skin lesion may be caused by different kinds of insects, thus it is difficult and Treatment often impossible to infer from a skin lesion the causative Insect bites are primarily treated with topical steroids and insect. However, in some cases, the clinical aspect and the oral antihistamines. Patients suffering from agonising distribution of the skin lesions may be suggestive: for nocturnal pruritus may benefit from the use of older, example, pruritic lesions caused by fleas and bed bugs are sedative antihistamines. In severe, disseminated or re- more frequently papular and typically clustered or linearly fractory cases, the oral intake of steroids may be required. grouped, which is rarely seen with mosquito bites [5e7]. The typical evolution of insect bites is the initial formation of wheals and flares (with a peak within 20 min), a delayed Myiasis reaction manifesting as itchy indurated erythematous pap- ules (with a peak at 24e36 h) and the gradual resolution of The maggots/larvae of various flies (mostly Dermatobia the lesions within days to weeks [8]. However, the clinical hominis [human bot fly e Central and South America] and Author's personal copy Diagnoses of common dermatological problems in returning travellers 339 Cordylobia anthropophaga [tumbu/mango/putzi fly e Sub- hygiene standards are low and acquired by direct contact with saharan Africa]) can cause infection in humans [76]. African infected individuals. Scabies mites (0.5 mm) burrow a tumbu flies lay their eggs in faecal-contaminated soil or on mostly invisible S-shaped tunnel of up to 4 mm into the su- damp clothing hanging to dry. Direct contact activates the perficial layer of the epidermis, where they live and lay eggs hatched larvae to penetrate the skin. American human bot [77]. The resulting skin lesions (Fig. 3) are most commonly flies attach their eggs to the body of captured mosquitos, to found on the fingers, especially in the web spaces, anterior reach the human host. wrists, upper limbs, axillary lines, the periumbilical region, external genitalia and buttocks [78]. As a result of a hyper- Diagnosis sensitive reaction to mite proteins, patients typically Diagnosis is based on the pathognomonic clinical picture, complain about intense itching, typically worst at night while which is characterized by itchy, slowly enlarging (Ø 1e3 cm) in the warm bed. Scratching itchy areas may result in bacterial subcutaneous furuncular (boil-like) skin lesions. On close superinfection. Diagnosis is frequently delayed, as the lesions inspection, a central aperture, permitting the maggot to are mistaken for eczema, tinea, or atopic dermatitis [79]. breathe and to drain waste products, is visible (Fig. 1). Diagnosis Treatment Diagnosis is mainly based on the clinical picture. The lesions The maggots can be removed by gently squeezing the boil, are best identified by a handheld dermatoscope. assisted by first covering the aperture with a layer of paraffin oil or petroleum jelly to stop the oxygen supply. Treatment While mature larvae are easily extracted by these mea- For practical reasons, although possibly less effective, oral sures, early lesions are best left to develop for a few days, ivermectin has largely replaced the cumbersome topical as immature maggots are reluctant to emerge. If surgical treatment with permethrin, benzyl benzoate, crotamiton removal is applied, rupture of the larvae has to be avoided, or lindane as the first-line treatment [78e80]. The as this can lead to a severe inflammatory reaction. currently recommended treatment regimens are two ap- plications (overnight) of topical permethrin 5%, 1e2 weeks Tungiasis (‘Sand flea’, ‘Jigger’) apart or oral ivermectin (200 mg/kg body weight) OD on day 1 and after 1e2 weeks [78]. Tungiasis is endemic in parts of Africa, Central and South America, and India. Tunga penetrans is the smallest of all Pitfalls/not to be missed fleas, measuring around 1 mm in length, and lives in the soil Non-healing or progressively ulcerating insect bites near pigsties and cattle sheds [77]. The female T. penetrans persisting over weeks or months should raise suspicions flea burrows into the soft skin regions of suitable hosts of cutaneous leishmaniasis (see below) (humans and various animals) and remains there for up to Consider Myiasis or Tungiasis in lesions showing a cen- five weeks, during which time it feeds on blood, matures, tral orification and produces and releases eggs, before finally dying [76]. Scabies may present a wide range of clinical pictures Erythema chronicum migrans in Lyme borreliosis Diagnosis Rickettsioses (see below) The lesions are commonly located at the feet and the clinical African/South American trypanosomiasis/sleeping picture is pathognomonic: the flea’s round whitish abdomen sickness (see below) shines through the overlying dermis around a central aper- ture (Fig. 2). The lesions may be pruritic and painful. Bacterial skin infections Treatment Bacterial infections are the most frequent skin disorder in Extraction of the parasite after removal of the overlaying travellers returning from tropical and subtropical countries.