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Scabies

Key Points Ectoparasite spread from person. Endemicity disease and epidemics relaxed to overcrowding and poverty. Female mite burrows into epidermis and lays eggs. Rash and itch result from papules / vesicles of individual mite in burrows plus secondary more generalized papular immune response. Secondary bacterial pyoderma occurs. Most severe disease in immunocompromised individuals called crusted (Norwegian) scabies. Topical scabicides cure infestation when correctly used. Treatment of contacts is…

Anthrax, Plague, Diphtheria, Trachoma, and Miscellaneous Bacteria

Anthrax Stephen K. Tyring Synonyms Bacillus anthracis toxins Key Points Anthrax is a fatal disease in domestic livestock and in wild herbivores. Humans are usually infected incidentally. Most human disease is cutaneous, followed by oral–oropharyngeal, gastrointestinal, and inhalational. Disease is mediated through toxins that cause edema, hemorrhage, and necrosis. Mortality rate is high. Diagnosis is clinical, biopsy, Gram stain, culture, or serology. Treatment is with penicillin, ciprofloxacin,…

Other Spirochetoses

Borreliosis (Lyme Disease) Claudia Pires Amaral Maia Christiane Maria De Castro Dani Synonyms Lyme disease (LD), cutaneous borreliosis, borreliosis, borrelial lymphocytoma, lymphadenosis cutis benigna, erythema chronicum migrans, erythema migrans, acrodermatitis chronica atrophicans Key Points This anthropozoonosis is endemic in North America and Europe. It is caused by Borrelia burgdorferi , a spirochete. The vector is the tick ( Ixodes ricinus complex ). Clinical manifestations: Early localized stage: erythema…

Bacterial Sexually Transmitted Disease

Introduction Bacterial sexually transmitted diseases (STDs) have become an important medical challenge worldwide, especially among the tropical countries. The ubiquitousness of STDs affects all nations and races, but is particularly evident in developing countries. Insufficient health-care centers, inadequate laboratory capabilities, and the unavailability of appropriate drug regimens of treatment perpetuate the prevalence of these STDs. However, it is important to appreciate that underservicing of areas and…

Bartonellosis

Introduction Bartonella bacilliformis was described more than 100 years ago as the cause of Carrión disease (CD) but it remained a medical curiosity until the description of bacillary angiomatosis (BA) in the late 1980s. The genus Bartonella has received great attention since, and research on the matter has flourished. This is a group of bacteria that are selective mammalian pathogens requiring specific vectors to be transmitted.…

Ehrlichioses

Key Points Fever, history of tick bite / tick exposure. Signs and symptoms are non-specific. Macular or maculopapular rash in approximately 30% of patients with HME; 2–5% in cases of HGA. In HME cases, rash is more frequent in the pediatric population (67%). Leukopenia and thrombocytopenia are frequent in the first week of illness. Detection of serum antibodies by indirect immunofluorescent assay (IFA) is the gold standard for…

Rickettsial Infections

Key Point Rickettsiae are obligately intracellular, Gram-negative bacteria that are transmitted when arthropods feed on humans. An important clue to diagnosing rickettsial disease is the eschar that forms at the site of an arthropod bite. First-line therapy for rickettsial infection consists of a tetracycline or chloramphenicol. Prompt administration of appropriate antibiotic therapy is the most effective measure for minimizing disease and preventing fatalities. Careful evaluation of…

Mycobacteria

Tuberculosis Leninha Valerio do Nascimento Caroline Fattori Assed Saad Synonyms Tisic, scrofula Key Points Mycobacteria. Tuberculosis. Tuberculides. Introduction Tuberculosis is one of the oldest diseases on earth, and affects the lungs, lymphatic ganglia, bones, intestines, skin, and other organs. Most often there is systemic dissemination of the bacilli from the primary infective foci during periods of lowered immunity. Cutaneous tuberculosis occurs when the bacillus reaches the skin by…

Staphylococcal and Streptococcal Pyodermas

Key Points Pyodermas caused by Gram-positive cocci are a significant cause of morbidity and comorbidity in developing countries. Antibiotic resistance, empiric and inadequate therapy, and cost of new antibiotics impede efforts to reduce prevalence of cutaneous skin infections. Toxin production is associated with increased severity and mortality of infections. Poststreptococcal glomerulonephritis may occur. Lack of resources (clean water, sanitation, public health surveillance) contributes to morbidity and…

Meningococcal Disease

Key Points Infections with bacteria of the species Neisseria meningitidis are the most common cause of community-acquired bacterial meningitis in young adults. The disease may occur in seasonal epidemics and it affects both children and adults worldwide. Severe flu-like symptoms predominate initially, with nausea, vomiting, headache, severe myalgias, rash, and possibly sepsis, with or without meningeal signs. 50% develop a petechial or purpuric cutaneous eruption with…

Systemic Fungal Infections

Introduction Without any doubt systemic fungal infections constitute public health and economic problems. Nowhere is this clearer than in tropical countries where these diseases are endemic, or at least have a high incidence. The World Health Organization (WHO) has acknowledged the importance of systemic tropical mycoses and has urged countries to recognize their impact and morbidity, and improve mycological awareness and capabilities. Dermatologists from all over…

Subcutaneous Mycoses

Introduction Subcutaneous mycoses are a group of fungal diseases produced by a heterogeneous group of fungi that infect the skin, subcutaneous tissue, and in some cases the underlying tissues and organs. The causative agents are commonly found in the soil, leaves, and organic material, and are introduced by traumatic injury of the skin. The diseases usually remain localized and slowly spread to the surrounding tissue; symptoms…

Superficial Mycoses and Dermatophytes

Introduction Fungal disease involving human keratinized tissue may be caused by dermatophytes, non-dermatophytic fungi, or a combination of both. Superficial disease caused by non-dermatophytes is limited to the stratum corneum, hair, or both. When fungi grow on the host, there is little to no host immune response. Cutaneous disease involves the epidermis and dermis and there is an inflammatory reaction similar to contact dermatitis. Because the…

Tropical Manifestations of Common Viral Infections

Key Points Environment and genetics may result in an altered clinical presentation of common viruses in the tropics. Epstein–Barr virus (EBV) can cause infectious mononucleosis, oral hairy leukoplakia, and chronic active EBV infection. EBV can also cause nasopharyngeal carcinoma, Burkitt's lymphoma, Hodgkin's disease, and mucocutaneous lymphomas. Human papillomavirus (HPV) can result in clinically severe benign tumors and carcinomas, due to inadequate therapy, co-infection with HIV, and…

Human T-lymphotropic Virus 1

Key Points HTLV-1. Tropical spastic paraparesia. Infective dermatitis. Crusted scabies. Adult T-cell leukemia lymphoma. Introduction The human T-lymphotropic virus 1 (HTLV-1) was the first retrovirus identified, even before the human immunodeficiency virus (initially called HTLV-3). It is a delta retrovirus currently linked to various clinical manifestations, from autoimmune disease (such as tropical spastic paraparesis) to immunodysregu­lation (as in the case of infective dermatitis), to infections (crusted…

Measles

Key Points Measles is a highly contagious mucocutaneous disease caused by the measles virus. It is one of the most important infectious diseases of humans, responsible for millions of deaths prior to the development of measles vaccines. It manifests as prodromal illness characterized by fever, cough, coryza, and conjunctivitis. Koplik's spots, small white lesions on the buccal mucosa, appear before the rash. Characteristic erythematous and maculopapular…

Poxviruses

Introduction Since the last natural smallpox infection, reported in Somalia in 1977, human poxvirus infections (other than molluscum contagiosum) have only been observed sporadically either after vaccination with poxvirus officinalis (vaccinia virus), or due to zoonotic poxviruses, such as monkeypox, catpox, or tanapox virus. As it is highly lethal and infectious, smallpox virus is feared for its potential use by bioterrorists. History Smallpox epidemics have decimated…

Hemorrhagic Fever and Arboviruses

Key Points Arenaviruses and hantaviruses are systemic viral diseases that are closely related to hemorrhagic fevers. Both groups of viral hemorrhagic fevers are shed in the infected rodent's saliva, urine, and feces. Ebola infection is the most aggressive viral hemorrhagic fever and is mainly restricted to Africa. Introduction Viruses are important pathogens in the tropical areas, most of them producing several mucocutaneous manifestations, especially among the…

HIV and HIV-associated Disorders

Introduction The pandemic of human immunodeficiency / acquired immunodeficiency syndrome (HIV / AIDS) is proving to be a modern scourge. The sheer magnitude of the problem can be understood, to some extent, by looking at the figures in Tables 11-1 and 11-2 . There were an estimated 36.9 million individuals infected with HIV at the end of 2014. There were an estimated 2 million new infections in 2014 (down from…

Trematodes

Key Points Infection takes place by skin contact with Schistosoma cercariae-infested water. Three clinical stages with distinctive skin manifestations are successively related to the different stages of infection: First stage (cercarial dermatitis): pruritic maculopapular rash at the site of penetration of the cercaria Second stage (acute schistosomiasis syndrome): urticaria associated with migrating and maturing larva Third stage (late cutaneous schistosomiasis): granulomatous cutaneous lesions in response to…