Allergic responses sensitization

SENSITIZER A substance that causes little or no reaction in a person upon initial exposure but which will provoke an allergic response on subsequent exposures. 

Platinum is used as a catalyst for nitric and sulphuric acid production, in petroleum refining and in catalytic mufflers to control air pollution. Platinum salts can cause respiratory complaints, asthma, and platinosis , an allergic response. Allergic dermatitis may also result from exposure to soluble platinum salts and once subjects have been sensitized it generally precludes continued occupational exposure at any level. The 8 hr TWA OEL for platinum metal is 5 mg/m but for soluble platinum salts it is only 0.002 mg/m. Handling precautions must include containment where possible, ventilation, personal protection, and the screening out of individuals who have become sensitized. 

Isolated cases of dermal sensitivity and allergic responses in humans have been reported (Bauer and Rabens 1974 Conde-Salazar et al. 1983 Czirjak et al. 1993 Goh andNg 1988 Nakayama et al. 1988 Phoon et al. 1984 Schattner and Malnick 1990 Waller et al. 1994). An increase in the symptoms of systemic lupus erythematosus has been reported in persons exposed to trichloroethylene in their drinking water (Kilbum and Warshaw 1992). 

FIGURE 59-1. Allergen sensitization and the allergic response. (From DiPiro JT, Talbert RL, Yee GC, et al, (eds.) Pharmacotherapy A Pathophysiologic Approach. 6th ed. New York McGraw-Hill 2005, Figure 93-1, p. 1730.)... 

Sensitizer A substance that may cause no reaction in a person during initial exposures, but afterwards, further exposures will cause an allergic response to the substance. 

Mast cells influence the long-term consequences and the resolution of CHS beginning 3 days after challenge of sensitized animals with DNFB or urushiol. Production of the immunosuppressive cytokine lL-10 by mast cells strongly contributed to these late anti-inflammatory effects of mast cells. Thus, this example demonstrates for the first time that mast cells are able to truly modulate - and not only to promote - allergic responses. 

Machado DC, Horton D, Harrop R, Peachell PT, Helm BA Potential allergens stimulate the release of mediators of the allergic response from cells of mast cell lineage in the absence of sensitization with antigen-specific IgE. 

Clinical expressions of cutaneous allergic reactions include eczematous, indurate-inflammatory, and urticarial eruptions. Irritant responses causing direct damage to the skin may be confused with allergic responses involving immune mechanisms. An important difference is that allergic reactions require an initial exposure to sensitize the individual dermatitis is then elicited by minimal subsequent exposure to the agent. 

In addition to the flush, wheal, and flare, transient pain and itching result from the effects of histamine on sensory nerve endings. In sensitized individuals, intra-dermal injection of specific antigens produces a wheal this reaction is the basis for a skin test to quantify the extent of the allergic response. 

Because trimethoprim accumulates in the prostate, TMP-SMX is used to treat prostatitis caused by sensitive organisms. Therapy can be prolonged (4-6 weeks) and repeat courses of therapy may be necessary. Trimethoprim alone, because of its lipid solubility, can be effectively used when patients exhibit an allergic response to the sulfonamide component. 

There is also a possibility that someone can develop a type IV delayed hypersensitivity to some monomers. Of the monomers used, TEGDMA and HEMA may have the highest incident of sensitivity, but that incidence is extremely low. Though there are no literature reports of toxicity to composite resins over the 30 years of dental use, there are investigations into the potential for at least an allergic response to degradation products or extractable components [181]. 

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