Study Set Content:
In contrast to phototoxicity, is a type IV delayed hypersensitivityreaction, leading typically to eczema.
Photoallergy
Comedogenic chemicals induce comedone lesions, which may be open or closed
Acne
one of the most disguring forms of acne in humans, is caused by exposure to polyhalogenated aromatic hydrocarbons.
Chloracne ─
Several actors influence pigmentation of the skin. • () is produced through a series of enzymatic pathways beginning with tyrosine. • Errors in this pathway or exposure to () analogs may result in abnormal pigmentation
Melanin, tyrosine
results from increased melanin production or deposition of endogenous or exogenous pigment in the upper dermis.
Hyperpigmentation
is a loss of pigmentation rom melanin loss, melanocyte damage, or vascular abnormalities
Hypopigmentation
An immediate type I hypersensitivity reaction •()) ─ are raised wheals that usually itch or sting and may appear reddish
utricaria (hives
Commonly resembles an upper respiratory tract infection in the first several days (fever, cough, sore throat, and malaise), but prompt diagnosis when the cutaneous lesions become evident several days later improves survival chances. • Most life-threatening dermatologic diseases that is caused by drugs and chemicals.
TOXIC EPIDERMAL NECROLYSIS (TEN)
A characteristic feature of the syndrome is the large-scale apoptosis of epidermal keratinocytes. o Anticonvulsants, NSAIDs, antibacterial sulphonamides, allopurinol, nevirapine
TOXIC EPIDERMAL NECROLYSIS (TEN)
Radiation from ionizing wavelengths to () has been shown to cause skin cancer.
ultraviolet wavelengths
─ abundant element in the earth’s crust that is encountered routinely in small doses in the air, water, and food. ─ smelting operations and from well water
Arsenic
Effects of Drugs on Human Sexual Differentiation ─ Exposure to hormonally active chemicals during sex differentiation can produce
Pseudohermaphroditism; diethylstillbestrol
Androgenic drugs like ()() can masculinize human females (i.e., “female pseudohermaphroditism”).
danazol and methyltestosterone
The drug (), which alters steroid hormone synthesis in a manner identical to many fungicides, also masculinizes human females following in utero exposure.
aminoglutethimide
of the developing fetus to DES causes clear cell adenocarcinoma of the vagina, as well as gross structural abnormalities of the cervix, uterus, and fallopian tube
Transplacental exposure
Organochlorine compounds in humans () and () has been associated with reproductive alterations in boys
PCB and PCDF
o pesticides and other toxic substances (i.e., chlordecone and DBCP) in the workplace has been associated with reduced fertility, lowered sperm counts, and/or endocrine alterations in male workers.
Occupational Exposures
inhibits prolactin, LH and FSH secretion
Cadmium
- also decrease LH and FSH
Lead and Mercury
- inhibit the release of LH, FSH as well as TSH (Example: polychlorinated biphenyls and polybrominated diphenylethers) Methoxychlor, dieldrin and endosulfan - increase prolactin and LH levels.
Environmental contaminants -
