Agents for hyperkeratosis

shevyatiwari's version from 2015-04-24 01:28

Salicylic acid

Question Answer
Willow bark contains ureaF, salicylic acid
Salicylic acid present in willow bark, wintergreen and sweet birch however is easily synthesisedT
SA is a B hydroxyacidF, is a phenol aromatic acid
Lipid insolubleF
As it is lipophilic, effects limited to superficial dermisF, epidermis
Reduces corneocyte adhesionT
Loosening and detaches corneocytsT
Removes intercellular lipids T
Extracts integral proteins from desmsomesT
Denatures membrane crossing glycoproteinsT
Desmolytic is preferred to keratolytic in SAT
Lyses or breaks intracellular keratin filamentsF, disrupts cellular junctions
SA results in a more regular and thin SCF, irregular
SA alters epidermal thicknessF
SA and derivatives can transform UVR into long wave radiation and therefore may have efficacy as sunscreensT
Salicylic acid has anti-inflammatory effects esp between 0.5-5%T
IF applied to erythrodermic skin, can be seen in the urine in 24 hoursT
Percutaneous absorption is increased with a lipophilic ointmentF, hydrophilic
Salicylate toxicity includes nausea, vomiting, confusion, dizziness, delirium, psychosis, stupor, coma and deathT
Tinnitus can occur due to salicylic toxicityT
Naproxen may cause increased toxicityT
Salicylate can cause hyeprglycaemiaF, hypo
SA is a weak sensitisier for ACDT
Absorbs UVAF, UVB
Optimal keratolytic effect when near it's pH of 2.98T


Question Answer
Antiseptic, antiparasitic, anti acne, anti seborrheic, anti viralF, not antiviral
Yellow metallic elementF, not metallic
Smaller particles have greater effectT. Not used much. Anti staph and anti candidial
Precipitated sulfur is the most commonly usedT
Colloidal sulfur is the most active form of sulfurT
Sulfur normalises keratinistaion and epidermal cell maturationT
Sulfur at high doses causes increased hydrogen sulphide ->break down of keratin and dissolution of SCT
Anti fungal activity only due to shedding of infected SCF, also due to pentathionic acid production by cutaneous bacteria and keratinocytes
Inhibits sulfhydryl groups in bacterial enzyme systemsT, ihhibits P acnes, Strep, S auerus
Can cause death of Demodex and scabiesT
Penetrates skin over 8 hoursT
Offensive odourT, rotten eggs
Has caused death in infantsT
Interaction with cysteine accounts for antibacterial effectF, keratolytic effect
In low concentrations is keratoplastic, in high concentrations is keratolyticT
Keratolytic effect dampened with SAF, enhanced
Use in acne related to keratolytic effectF, due to irritant effect -> peeling
20% colloidal sulfur can be used for scabies in pregnant womenF, 5-10% of precipitated


Question Answer
Product of organic matter heated in the absence of oxygenT
Tar is derived from bituminous coal, wood and marine fossilsT
Crude coal tar is the most commonly usedT, produced from gases. Solid form is coke
Crude coal tar contains a single active ingredientF, made of thousands of individual organic components
Alcohol extract of coal tar emulsified with polysorbate yields LPCF, LCD
Tar derived from wood is more irritating and toxic but is less carcinogenicT
Tar derived from bituminous tar is aka sulfonated shale oilT
Bituminous tar is always darkF, can be light too
Tar is anti proliferative and causes thickening of the epidermisF, progressive thinning that follows a transient epidermal hyperplasia secondary to irritation
Tar suppresses RNAF, DNA synthesis -> decreased mitotic activity in basal layer
Potentiated activity in combination with UVT
Shale tar is anti-inflammatory by inhibiting chemotaxis of eosinophils due to leukotriene B4 and C5aF, neutrophils
Shale tar has anti fungal mechanisms which are largely unknownT
Coal tar can be used for dermatophyte infectionF, only Shale tar - in shampoos
Can be compounded up to 20%T
Incidence of skin cancer is increased as mono therapyF, only in combination with UVR
Goekerman therapy may have genotoxic effectsT
Scrotal SCC is associated with tar exposureT
Shale oil has low levels of carcinogenic agentsT
Major carcinogenic agents are PAH and pyridinesT. Coal tar has lots, wood tar has PAH and bituminous has low levels of both (Shale oil)
Coal tar is aesthetically pleasingF
Wood tar is the most phototoxicF, coal tar is. Wood and bituminous don't, and are cosmetically better
Phototoxic reactions can cause poikilodermaT
Contact dermatitis is most common with wood tar, and can cross react with colophony, balsam of Peru, turpentineT
Tar can cause KA'sT, also acne, folliculitis, , comedones, keratoses


Question Answer
Urea is highly water solubleT
When mixed with NaCL, water binding capacity of urea decreasesF,increases
Urea can cause bacterial growthF, inhibits growth of some microorganisms
Urea enhances absorption of various chemicals and agentsT
Urea is an occlusiveF, humectant
Urea can increase penetration of TCST
High urea concentrations can cause protein denaturationT
Can macerate dystrophilc nailsT
Bipolar structure allows keratin dispersing and denaturing capabilities without disrupting the epidermal water barrierT
Promotes keratolysis bu improving hydration in the horny layerT
Urea acts as an emollientT
Concentrations up to 40-50% can be used for dry skinF, for calluses
Can be used for avulsion of nailsT, 40% urea, 20% anhydrous lanolin, 5% white wax, 35% white petrolatum under occlusion
Can be used IL for BCC and SCCT
Can be used for wound healingT
Can cause irritation and macerationT
Excoriations and fissured skin show no S/EF, stinging and irritation. Related to high acidity of many preparation s(pH of 3 or less)

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