Skin hyper-irritability

Another factor to consider is that patients with endogenous skin disease are frequently more susceptible to cosmetic reactions. One reason is that patients with preexisting skin disease may have skin barrier dysfunction, with consequent increased permeability. Skin hyper-reactivity in atopic patients, particularly, has been gathering interest in recent years. Epidemiologic associations between atopic dermatitis and irritant dermatitis are now supported by skin bioengineering data.25... 

Many irritative chemicals may cause non-specific hyper-responsitivity of the airways and skin. The number of irritating chemicals is very large, several thousands. The symptoms caused by exposure to irritants may resemble allergic symptoms. In addition, exposure to irritating substances (such as sulfur dioxide or solvent vapors) often triggers the symptoms in individuals with allergic asthma. 

Measurement of differences in skin reactivity or sensitivity among individuals plays an important role in the workplace, as well as in the manufacture of safe topical therapeutics and cosmetics. Outlined in the following sections are objective and subjective methods of quantifying the reactivity of human skin to chemicals, which are potential irritants.6 The experimental basis of such testing is to quantify the differences among individuals to chemicals that produce characteristic responses using a standard reproducible procedure. Individuals classified as hyper-reactors (sensitive skin) and hyporeactors can then be identified. 

HEALTH SYMPTOMS Inhalation (pulmonary effects, injury to liver, irritates eyes, nose and throat) contact (acne-skin rash, dermatitis, hyper-pigmentation) ingestion (gastrointestinal disturbances, yellowjaundice, dark urine, fatigue). 

CHRONIC HEALTH RISKS irritation of skin and mucous membranes dermatitis rhinitis pharyngitis conjunctivitis skin lesions hyper-pigmentation gangrene of the extremities vascular lesions exfoliation herpes appearance of small corns or warts increased risk of nonmelanoma skin cancer lung cancer bladder and liver cancer tumors of mouth, esophagus, larynx, bladder, para nasal sinus liver or kidney damage lower than normal birth weights. 

HEALTH SYMPTOMS inhalation (cough, sore throat, irritates eyes, skin and respiratory tract) skin absorption (numbness, coarse tremors, fatigue, weakness, convulsions, respiratory failure) ingestion (anesthesia, headache, convulsions, cardiac arrhythmias, nausea, vomiting, sweating, diarrhea, hyper-excitability, paresthesias of tongue, lips and face). 

In the past few decades, the various activities such as antioxidant, cell inflammation, antimutagenic, and toxicity of capsaicinoid compounds have been investigated and reported by many researchers and scientists. Materska and Perucka reported the determination of the antioxidant activity of the capsaicinoid compounds isolated from hot and semi-hot pepper fruits at two different maturity stages during their cultivation [26], Reilly et al. have found that capsaicinoids are able to activate the vanilloid receptors, which are responsible for inflanunation and epithelial cell death in animal and human bodies [27,28]. The characteristic pharmacological responses of capsaicinoids include severe irritation, inflanunation, erythema, and transient hyper- and hypoalgesia at exposed sites such as, eyes, skin, nose, tongue, and respiratory tract. The vanilloid receptors are the calcium channel when activated by capsaicinoids they produce the characteristic sensations and causes toxicity in many mammalian cell types [27-29],... 

From a practical point of view, post-irritative hypo-reactivity probably represents another aspect of skin adaptation to environmental influences. Whereas post-irritant hyper-reactivity would explain the greater irritability of eczematous skin during patch testing, a hypo-reactive state may cause false negative patch-test results for as long as 9 weeks after an irritant reaction. 

It may be argued that the patch tests are positive because the skin is in a state of hyper-reactivity termed excited-skin syndrome or angry back (Bruynzeel and Maibach 1995). This may lead to strong positive reactions to patch tests of minor irritants or subclinical or weak allergens. Authors who report compound allergies, such as Cox et al. (1989) or Kellett et al. (1986), have eliminated this as far as possible by repeating the patch tests 2 months later and obtaining another positive result. 

The characteristic symptoms of human poisoning by Type I pyrethroids are tremors, hypersensitivity, hyper-excitability, muscle cramps and seizures, while the main symptoms of poisoning by Type II pyrethroids are choreoathetosis, salivation, lach-rymation, nasal hyper-secretion, hypersensitivity, cutaneous sensory disturbances (tingling, numbness and burning sensation), skin irritation, headache, loss of appetite, fatigue, dizziness, loss of consciousness, muscle cramps and seizures (Appel et al. 1994 Barrot 1996). 

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