Thickening of the skin’s outer layer due to an increased amount of keratin.
The most common forms of hyperkeratosis affect small, localized areas of skin and include corns, calluses and warts.
A rare, inherited form affects the whole of the soles and palms.
The term hyperkeratosis may also be used to describe thickening of the nails.
Thickening of the horny (outer) layer of skin, affecting the palms of the hands and soles of the feet. The disorder may be inherited.
n. thickening of the outer horny layer of the skin. It may occur as an inherited disorder, affecting the palms and soles. —hyperkeratotic adj.
A metalloid with industrial use in glass, wood preservative, herbicide, semiconductor manufacture, and as an alloy additive. It may be a component in alternative or traditional remedies both intentionally and as a contaminant. Common in the environment and in food, especially seafood, arsenic is odourless and tasteless and highly toxic by ingestion, inhalation and skin contact. It binds to sulphydryl groups inhibiting the action of many enzymes (see ENZYME) and also disrupts oxidative phosphorylation by substituting for PHOSPHORUS. Clinical effects of acute poisoning range from severe gastrointestinal effects to renal impairment or failure characterised by OLIGURIA, HAEMATURIA, PROTEINURIA and renal tubular necrosis. SHOCK, COMA and CONVULSIONS are reported, as are JAUNDICE and peripheral NEUROPATHY. Chronic exposures are harder to diagnose as effects are non-speci?c: they include gastrointestinal disturbances, hyperpigmentation and HYPERKERATOSIS of skin, localised OEDEMA, ALOPECIA, neuropathy, PARAESTHESIA, HEPATOMEGALY and jaundice. Management is largely supportive, particularly ensuring adequate renal function. Concentrations of arsenic in urine and blood can be measured and therapy instituted if needed. Several CHELATING AGENTS are e?ective: these include DMPS (2, 3-dimercapto-1-propanesulphonate), penicillamine and dimercaprol; DMPS is now agent of choice.... arsenic
A non-venereal spirochaetal infection caused by Treponema pertenue ; it was formerly widespread in most tropical and subtropical regions amongst the indigenous population, ?orid disease being more common in children than adults. The term is of Carib-Indian (native to north-eastern South America, the east coast of Central America, and the lesser Antilles) origin. It is directly contagious from person to person; infection is also transmitted by ?ies, clothing, and living in unclean huts. Clinically, the primary stage is characterised by a granulomatous lesion, or papule (framboesioma or ‘mother yaw’) at the site of infection – usually the lower leg or foot; this enlarges, crusts, and heals spontaneously. It appears some 2–8 weeks after infection, during which time fever, malaise, pains, and pruritus may be present. In the secondary stage, a granulomatous, papular, macular or squamous eruption occurs; periostitis may also be present. The late, or tertiary stage (which appears 5–10 years later), is characterised by skin plaques, nodules, ulcers, hyperkeratosis (thickening of the skin of the hands and feet) and gummatous lesions affecting bones. Recurrence of infection in individuals suffering from a concurrent infection (e.g. SYPHILIS or TUBERCULOSIS) renders the infection more serious. Diagnosis is by demonstration of T. pertenue in exudate from a suspected lesion. Treatment is with PENICILLIN, to which T. pertenue is highly sensitive. Extensive eradication campaigns (initiated by the WHO in 1949) have been carried out in endemic areas; therefore, the early stages of the infection are rarely counted; only tertiary stages come to the attention of a physician. Failure of surveillance can lead to dramatic local recurrences.... yaws
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