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Poison Ivy/Oak/Sumac
Published in Charles Theisler, Adjuvant Medical Care, 2023
Poison ivy causes characteristic thin, red, raised lines in a whip-like appearance on the skin. The rash typically takes a few days to develop in full. Poison ivy treatments are usually limited to self-care methods since the rash typically goes away on its own in two to three weeks.
Eczema (dermatitis)
Published in Rashmi Sarkar, Anupam Das, Sumit Sethi, Concise Dermatology, 2021
The rash develops at the sites of skin contact with the ‘allergen’ but occasionally spreads outside these limits for unknown reasons. The severity and area of involvement vary enormously depending on the ‘dose’ of allergen to which the patient has been exposed and the susceptibility of the individual. When very acute, the reaction develops within a few hours of contacting the responsible substance; e.g. with ‘poison ivy’, which is common in the USA. Itching is noticed as a sign after exposure first and then the area involved becomes red, swollen, and vesicular. Later, the area becomes scaly and fissured.
The Integumentary (Dermatologic) System and Its Disorders
Published in Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss, Understanding Medical Terms, 2020
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss
Hypersensitivity to food, drugs, or physical agents; infections; or stress may produce a transient condition called urticaria, commonly referred to as "hives." This is a reaction of the blood vessels with the appearance of slightly elevated red or pale patches or wheals accompanied by severe itching. Allergic contactdermatitis is most often caused by poison ivy. Poison oak and sumac contain the same sensitizing oleoresin and produce the same inflammation. Typically, the rash is erythematous, vesicular, and sometimes oozing and ulcerated. Other agents that frequently cause allergic contact dermatitis include soaps, detergents, and fragrances. The term contact dermatitis is also frequently used generically for any skin inflammation, even without a hypersensitivity reaction; for example, a reaction to a caustic may sometimes be described as a contact dermatitis, although the term technically should be reserved for allergic reactions.
Himalayan poisonous plants for traditional healings and protection from viral attack: a comprehensive review
Published in Toxin Reviews, 2022
Shriya Pathania, Diksha Pathania, Priyanka Chauhan, Mamta Sharma
Hay fever caused by pollen from ragweed, birch, hazel, timothy grass, and ryegrass is the common case of phytoallergy. Urticaria resulting from eating strawberries and allergy to peanuts are some other recognized allergy conditions due to phytoconstituents. Some phytoconstituents cause certain forms of extrinsic allergic alveolitis. Pyrethrum allergy is a known problem on the plantations of Chrysanthemum cineriaefolium in many countries. The Japanese cedar (Cryptomeria japonica) is a source of annual misery because of the massive amounts of highly allergenic pollen every spring (Wink and Van Wyk 2008). A Phytoallergic problem has increased greatly in recent decades. A different allergic mechanism occurs in regions with poison ivy (Rhus toxicodendron, T. rydbergii), poison oak (Rhus juglandifolia) and poison sumac (Rhus vernix). The active ingredient is urushiol. Its first exposer of sap to the skin has no noticeable clinical effect. Urushiol acts as a hapten, however. It binds to proteins in the skin, creating new epitopes. Upon subsequent contact pronounced pruritic dermatitis develops (Wink 2010).
Clinical and immunologic differences in cellulitis vs. pseudocellulitis
Published in Expert Review of Clinical Immunology, 2021
Michael Goldenberg, Henry Wang, Trent Walker, Benjamin H Kaffenberger
Allergic contact dermatitis (ACD) is a delayed type IV hypersensitivity reaction resulting from allergen-specific T cell activation [50]. When it is misdiagnosed as cellulitis, it is most often related to abrupt exuberant exposure such as plant dermatitis, ultraviolet light exposure, or paraphenylenediamine in hair dye. It is extremely unlikely for a rinse-off product like shampoo, detergents, or soaps to cause an abrupt reaction that could be confused with cellulitis. This condition typically starts with extensive itching, redness, microvesiculations in the skin, and develops into large bullae if severe. The presence of itch is often a distinguishing factor. In addition, linear streaks, scattered black dots (presence in urushiol-related dermatitis from poison ivy), and geometric patterns should help clinically differentiate patients.
Bioactivation of herbal constituents: mechanisms and toxicological relevance
Published in Drug Metabolism Reviews, 2019
Urushiol (Figure 11(h)), a pale-yellow oily mixture of catechols with an alkyl side chain, are the allergenic components of Toxicodendron radicans (poison ivy) and Toxicodendron diversilobum (poison oak). Brushing up against these plants results in allergic contact dermatitis, leading to an itchy rash. Oxidation of urushiols to ortho-quinones likely results in depletion of intracellular GSH and covalent modification of macromolecules leading to skin toxicity (Dunn et al. 1982). Urushiol-induced contact dermatitis is known to be mediated by T lymphocytes that recognize urushiol-bound proteins as an antigen (Dunn et al. 1982). Urushiol ortho-quinones and/or ROS production are likely also responsible for the DNA fragmentation observed in human cancer cells treated with urushiol leading to induction of apoptosis (Kim et al. 2013).