Marginal irritant

Marginal irritant A material that is capable of causing an irritation response after repeated exposures. 

Ethanol, methyl ethyl ketone and acetone are recommended vehicles for patch tests of materials and products brought to the physician by patients, indicating that vast experience has demonstrated these solvents to be only marginal irritants (Wahlberg 1995b). Propylene glycol has irritant properties under occlusion, and the optimal test concentration and vehicles are not yet settled (Wahlberg 1994). 

Tosylamide formaldehyde resin, 10% in petrolatum Nitrocellulose 10%, in isopropyl alcohol Dibutyl phthalate, 5% in petrolatum Formaldehyde, 1% aqueous Methyl acrylate, 1.5% in petrolatum Benzalkonium chloride, 0.01-0.1% aqueous (0.1% is a marginal irritant)... 

The risk characterization is carried out by quantitatively comparing the outcome of the hazard (effects assessment) to the outcome of the exposure assessment, i.e., a comparison of the NOAEL, or LOAEL, and the exposure estimate. The ratio resulting from this comparison is called the Margin of Safety (MOS) (MOS = N(L)OAEL/Exposure). This is done separately for each potentially exposed population, i.e., workers, consumers, and man exposed via the environment, and for each toxicological endpoint, i.e., acute toxicity, irritation and corrosion, sensitization, repeated dose toxicity, mutagenicity, carcinogenicity, and toxicity to reproduction. 

The first sedative-hypnotic, or minor tranquilizer, bromide, originated in the 1860s. Bromides are long-acting sedatives that were rarely used past the turn of the nineteenth century however, bromide can still be found in Bromo Seltzer. The bromides are gastric irritants with a narrow safety margin and may cause a chronic toxicity known as bromism. 

Finn, an anesthetic cocktail used to lure sailors to the Orient in the 1800s. It has a rapid onset, short duration, and few cardiovascular or respiratory effects. Its side effects include an unpleasant taste, gastric irritation, nausea, vomiting, lightheadedness, and nightmares. It has a low margin of safety. 

These are conducted to gain information on the cumulative irritancy of a product. This type of test is designed to mirror the intended use of the product, but exposure may also be exaggerated, to provide a greater margin of safety in the risk assessment on the product and also to provide information on problems that may be encountered should the product be misused. Some methods are designed to simulate the normal use of products, with controlled exposure. The skin irritation is monitored and comparisons made between the test and control product in the same panellist. The controls are... 

Although solutions are the most commonly used vehicles for topical ocular medications, ointments are also frequently used for application to the eye. When applied to the inferior conjimctival sac, ophthalmic ointments melt quickly, and the excess spreads out onto the lid margins, lashes, and skin of the lids, depending on the amount instilled and on the extent of lacrimation induced by any irritation.The ointment at the lid margins acts as a reservoir and enhances drug contact time. 

The most freqnently reported reactions to topically applied snlfonamides are local irritation, stinging, and binning. Contact dermatitis is common with topical application of these dmgs, and they can cause more serious dermatologic problems such as erythema nodosum, erythema multiforme (Stevens-Johnson syndrome), and exfoliative dermatitis. In addition to hypersensitivity reactions, topical administration of snlfonamides can lead to local photosensitization, which can result in sunburn on the Ud margins or skin of the face. 

Severe itching and irritation characterize phthiriasis palpebrarum. Blepharoconjunctivitis, blood-stained thickened discharge from fecal matter on the lid margins, nits, and adult parasites on the eyelashes may all be visible. 

Anticholinesterase agents, such as 0.25% physostig-mine ointment, are also a viable treatment option and may be applied to the lid margins. Side effects, such as miosis and browache, may limit their use. Gamma benzene hexachloride should be avoided on treating the lid condition because of potential ocular irritation and... 

Verrucae are self-limiting but can be very serious in the immunosuppressed. Treatment is primarily cosmetic but also prevents further dissemination. Most verrucae lesions resolve spontaneously after several months to years therefore therapy should be conservative. Because the lesions are localized to the epidermis, most treatments are limited to this level and should not result in scarring. Benign treatments include topical applications of irritants salicylic acid and lactic acid, applied under an occlusive barrier, can be purchased over the counter. More advanced treatment modalities include cryotherapy, surgical removal, or electro-or chemical cautery. Neither of these cautery methods is suitable for lesions on the lid margin because of the risk to the ocular surfece. 

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