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Aquatic skin diseases from chemical and physical causes
No full textVarious dermatological conditions with physical and chemical causes are connected with salt- or freshwater. Aquagenic urticaria, induced simply by skin contact with the water, regardless of its physical and chemical properties, starts some minutes after the contact and resolves after about an hour: the lesions are intensely itchy and punctiform. Cold urticaria, that features skin or mucosal pomphoid lesions that develop after contact with cold water or after the ingestion of cold drinks or foods, presents under various guises: familial or acquired, immediate or delayed, localized or systemic, primitive or secondary. Aquagenic pruritus manifests during bathing or immediately after coming out of the water and lasts some minutes or hours; in many cases it is observed in patients with polycythaemia rubra vera. Prolonged immersion in seawater causes electrolytic alterations due to percutaneous absorption (“immersion syndrome”). Swimmers, hydrotherapists, physiotherapists, cleaners and swimming pool attendants present dehydration of the skin and hair because of the chlorine and bromine compounds used to disinfect the water. Both professional and amateur scuba divers are exposed to a variety of risks including skin complaints. An occupational chronic traumatic scleroedema of the hands, of various etiologies, is frequently observed in fishermen; the complaint, that can also affects the forearms, can persist for many years after abandonment of the work activity
Bacillus Calmette-Guerin
No full textApproximately one third of the world population is infected by Mycobacterium
tuberculosis, and a greater and continuing factor that is bolstering the ongoing
tuberculosis (TB) epidemic is the human immune deficiency virus (HIV). Further
complicating the issue, multidrug resistance (MDR) has arisen worldwide, and by
early 2010, 58 countries had reported at least one case of extensively drug resistant
TB . For all these reasons, TB prevention through vaccination is a key global
health priority.
Various vaccines have been shown to reduce the risk of disease and mortality
due to TB in man, but only one has been used in global immunization programs:
the M. bovis bacillus Calmette-Guérin (BCG). BCG is an attenuated live vaccine
administered at birth to children in most countries where TB is endemic. It is the
vaccine most widely used all over the world, and an estimated three billion doses
have been administered to date. Despite having reduced the burden of TB in
many zones, the BCG has various limitations and so the development of more efficacious
vaccines against TB is an extremely urgent issue. The ideal vaccine
should prevent both the initial tubercle infection and the development of active
disease, or reactivation in previously infected healthy hosts as well as in particularly
vulnerable populations (HIV-infected and other immunocompromised individuals)
Dermatitis caused by aquatic worms
No full textVarious aquatic worms induce injuries by traumatic or poisonous mechanisms, through bites or contact with the bristles on their bodies. Cercarial dermatitis, induced by non human-parasitizing schistosomes in bathers and underwater divers, can also be observed in subjects working with freshwater for irrigation purposes (agricultural workers and rice growers). Clinical manifestations are observed in allergic subjects. Leeches, that inhabit freshwaters, inject an anticoagulant and other antigenic substances with their bites: in allergic subjects there may be the onset of urticarial, blistering or necrotic and even anaphylactic reactions. The Polychaeta venom apparatus is present in the bristles and jaws, and can induce local skin reactions and anaphylactic reactions. Fishermen using lines can present with a peculiar contact dermatitis of the fingertips and nails of the hands, due to the coelomic liquid of a marine annelid worm used as bait. Larva migrans cutanea (“creeping eruption”), induced by the migration of nematode larvae through the skin, presents with linear erythemato-papular lesions, slightly raised above the surrounding skin. Oncocerciasis, caused by a nematode, affects the skin and eyes (“river blindness”). Skin manifestations can show a morphological evolution over time. Acute erythemato-papulous exanthematic pruriginous eruptions evolve to diffuse lichenification and, in a further phase, to hypotrophy or atrophy and hypo- and achromic lesions (a “leopard skin appearance”). Delayed skin complaints can manifest with onchocercomata, while involvement of the lymph nodes leads to elephantiasis of the genitalia
Mycobacterium bovis skin infection
No full textThe bovine tubercle bacillus must firstly be placed in context among the other
agents of tuberculosis. In the early decades of the twentieth century, bacteriologists
recognized four varieties of tubercle bacilli (human, bovine, avian and
cold-blooded), depending on the life forms from which they were isolated. By the
middle of the century, only two varieties were still recognized as agents of human
and bovine tuberculosis (TB), namely Mycobacterium tuberculosis and M. bovis, respectively.
In the 1960s, another TB agent was isolated in Africa, and named M. africanum, but this was later seen to include two varieties. Finally, in the 1980s it was
found that two varieties of M. tuberculosis itself could also be distinguished: classical
and Asian. This group of organisms, to which M. microti, M. pinnipedii,
M. canettii, and M. caprae were later added, is denominated the M. tuberculosis
complex . The bacillus Calmette-Guérin (BCG) was classed with M.
bovis. The avian and cold-blooded tubercle bacilli were then classified separately:
the first, that includes M. avium and M. intracellulare, is included in the M.
avium complex (together with M. lepraemurium and M. paratuberculosis), while
the second includes M. chelonae and M. fortuitum
Mycobacterium scrofulaceum infection
No full textMycobacterium scrofulaceum is a member of the Runyon class II scotochromogen
acid-fast bacilli. It is widely present in nature, but is now an infrequent human
pathogen. It was first described in the 1950s and the name likely derives from
its isolation from cervical lymph nodes
Mycobacterium ulcerans infection
No full textMycobacterium ulcerans is the causative agent of a new emerging infectious disease,
which has been reported in at least 33 countries worldwide with tropical, subtropical
and temperate climates.
Classified by the WHO as one of the 17 neglected tropical diseases,
M. ulcerans infection is the third most common mycobacterial disease in the world,
after tuberculosis and leprosy. In East Africa, where it is endemic and thousands of
cases are observed annually, the infection is the second most important mycobacterial
disease after tuberculosis.
Buruli ulcer disease (the name adopted for this infection worldwide) is often
referred to as the “mysterious disease” because the mode of transmission remains
unclear, although several hypotheses have been proposed. It is a serious necrotizing
infection due to a toxin, mycolactone, produced by the bacilli, that necrotizes
the subcutaneous tissue leading to deep ulceration. This is the most severe
form of the disease. Early detection before ulceration is therefore the key to
prompt cure; otherwise, if diagnosed late, the infection may leave patients with
disabling sequelae, such as scarring contractures and possible bone destruction
requiring amputation
Allergic contact dermatitis caused by Glycofilm® 1.5P contained in an anti-wrinkle cream
No full textN/
Dermatitis caused by molluscs
No full textOf the five classes belonging to this phylum, three are particularly toxic: Lamellibranchs, that have a bivalve shell (mussels, clams, oysters, scallops), Gasteropods (nude or covered by a shell) and Cephalopods (octopus, squid, cuttlefish). The bivalves do not produce toxins but because they are filtrating animals they can ingest microrganisms that produce biotoxins, and so become poisonous. Among the Gasteropods, some species of the Conidae family (with conical shells) have a well-developed venom apparatus and can kill a man. A cone shell sting immediately elicits intense burning sensations, torpor and tingling, which rapidly spread from the affected area to the whole body. There may also be disorders of speech and vision (double images, blurred vision). These symptoms are followed by ischemia and cyanosis in the affected area and, in severe cases, by muscular paralysis and coma. The bites of Cephalopods can induce both local and systemic reactions. For instance, the bite of a small venomous octopus (“blue-ringed octopus”) that populates the coasts of Australia may be fatal to man. It is found in tidal rock pools and is very attractive, particularly to children and tourists. Its tetrodotoxin causes the blockade of neuronal sodium channels, leading to weakness, numbness or paraesthesia, breathing difficulties and respiratory paralysis. The onset of the symptoms occurs 5-10 min after the bite. At the site of the wound there is typically prolonged copious bleeding, and an associated urticarial eruption is possible. There is no effective antidote; the treatment is symptomatic and must be administered in a hospital setting
Dermatitis caused by echinoderms
No full textThere are about 80 species of toxic or venomous Echinoderms. In particular, sea urchins, with their spine-covered bodies, are poisonous and can induce various types of reaction in man both when eaten as seafood and when they sting. In the first case, because of the toxins present in their gonads, the symptoms, although rarely fatal, will include gastrointestinal disorders and allergic reactions. Contact with the spines, that are sharp and very fragile, induces immediate and delayed reactions. Penetration of the spines into the skin causes immediate, burning pain, followed by erythema and edema, and there may be abundant bleeding from the affected part. Systemic symptoms can also develop, including nausea, muscle cramps, and respiratory distress. These symptoms can last up to 1-2 weeks, provided that the spines are immediately and completely removed. Delayed reactions are notoriously nodular granulomatous lesions, mostly considered to be non immunological reactions to a foreign body. Starfish can induce an urticarial clinical picture due to their toxins released in the water, as well as nodular granulomatous lesions after contact with the spines, that can be associated with very severe systemic symptoms. Again as a result of a toxic substance released into the water, seacucumbers can induce an irritant contact dermatitis and ocular lesions that can even end in blindness
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