The triple response of Lewis is a cutaneous response that occurs from firm stroking of the skin. This produces an initial red line, followed by a flare around that line, and then finally a wheal.
The triple response of Lewis is a cutaneous response that occurs from firm stroking of the skin. This produces an initial red line, followed by a flare around that line, and then finally a wheal.
The triple response consists of three aspects:
The red spot emerges within 15 seconds. [4] Flare can take up to 45 seconds to begin. [4] Wheal can take up to 3 minutes to begin. [4] [5]
The triple response is caused by firm stroking of the skin with a pointed object. [5] but some time at caused by capillary vasodilation. The triple response of Lewis is particularly sensitive in people with dermatographia urticaria. [4] [5] Some form of dermatographia is present in around 5% of the population. [4]
The triple response of Lewis is due to the release of histamine. Histamine, or 2-(imidazol-4-yl)ethanamine, is a dibasic vasoactive amine that is located in most body tissues but is highly concentrated in the lungs, skin, and gastrointestinal tract. Histamine is a small molecule, stored in granules of mast cells and basophils. Mast cells and basophils are the effector cells involved in the immediate hypersensitivity response. Found in tissues throughout the body, they are particularly associated with blood vessels and nerves, and are in proximity to surfaces that border the external environment.
The underlying pathophysiology of frostbite is a combination of freezing, vascular insufficiency (constriction and occlusion) and damage due to inflammatory mediators. As extremities cool, the ‘hunting response of Lewis’ (alternating vasoconstriction and vasodilation) occurs, ending with vasoconstriction. [1]
Blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away from the tissues. Blood vessels are needed to sustain life, because all of the body's tissues rely on their functionality.
A mast cell is a resident cell of connective tissue that contains many granules rich in histamine and heparin. Specifically, it is a type of granulocyte derived from the myeloid stem cell that is a part of the immune and neuroimmune systems. Mast cells were discovered by Paul Ehrlich in 1877. Although best known for their role in allergy and anaphylaxis, mast cells play an important protective role as well, being intimately involved in wound healing, angiogenesis, immune tolerance, defense against pathogens, and vascular permeability in brain tumors.
Basophils are a type of white blood cell. Basophils are the least common type of granulocyte, representing about 0.5% to 1% of circulating white blood cells. However, they are the largest type of granulocyte and how they work is not fully understood. They are responsible for inflammatory reactions during immune response, as well as in the formation of acute and chronic allergic diseases, including anaphylaxis, asthma, atopic dermatitis and hay fever. They also produce compounds that coordinate immune responses, including histamine and serotonin that induce inflammation, and heparin that prevents blood clotting, although there are less than that found in mast cell granules. Mast cells were once thought to be basophils that migrated from the blood into their resident tissues, but they are now known to be different types of cells.
Histamine is an organic nitrogenous compound involved in local immune responses communication, as well as regulating physiological functions in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. Since histamine was discovered in 1910, it has been considered a local hormone (autocoid) because it lacks the classic endocrine glands to secrete it; however, in recent years, histamine has been recognized as a central neurotransmitter. Histamine is involved in the inflammatory response and has a central role as a mediator of itching. As part of an immune response to foreign pathogens, histamine is produced by basophils and by mast cells found in nearby connective tissues. Histamine increases the permeability of the capillaries to white blood cells and some proteins, to allow them to engage pathogens in the infected tissues. It consists of an imidazole ring attached to an ethylamine chain; under physiological conditions, the amino group of the side-chain is protonated.
Vasodilation, also known as vasorelaxation, is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, which is the narrowing of blood vessels.
A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this system is as a barrier against the external environment.
Hives, also known as urticaria, is a kind of skin rash with red, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and does not leave any long-lasting skin change. Fewer than 5% of cases last for more than six weeks. The condition frequently recurs.
Dermatographic urticaria is a skin disorder and one of the most common types of urticaria, affecting 2–5% of the population.
Urticaria pigmentosa (also known as generalized eruption of cutaneous mastocytosis (childhood type) ) is the most common form of cutaneous mastocytosis. It is a rare disease caused by excessive numbers of mast cells in the skin that produce hives or lesions on the skin when irritated.
Darier's sign is a change observed after stroking lesions on the skin of a person with systemic mastocytosis or urticaria pigmentosa.
A pyogenic granuloma or lobular capillary hemangioma is a vascular tumor that occurs on both mucosa and skin, and appears as an overgrowth of tissue due to irritation, physical trauma, or hormonal factors. It is often found to involve the gums, skin, or nasal septum, and has also been found far from the head, such as in the thigh.
Physical urticaria is a distinct subgroup of urticaria (hives) that are induced by an exogenous physical stimulus rather than occurring spontaneously. There are seven subcategories that are recognized as independent diseases. Physical urticaria is known to be painful, itchy and physically unappealing; it can recur for months to years.
A cutaneous nerve is a nerve that provides nerve supply to the skin.
The axon reflex is the response stimulated by peripheral nerves of the body that travels away from the nerve cell body and branches to stimulate target organs. Reflexes are single reactions that respond to a stimulus making up the building blocks of the overall signaling in the body's nervous system. Neurons are the excitable cells that process and transmit these reflex signals through their axons, dendrites, and cell bodies. Axons directly facilitate intercellular communication projecting from the neuronal cell body to other neurons, local muscle tissue, glands and arterioles. In the axon reflex, signaling starts in the middle of the axon at the stimulation site and transmits signals directly to the effector organ skipping both an integration center and a chemical synapse present in the spinal cord reflex. The impulse is limited to a single bifurcated axon, or a neuron whose axon branches into two divisions and does not cause a general response to surrounding tissue.
Nevus anemicus is a congenital disorder characterized by macules of varying size and shape that are paler than the surrounding skin and cannot be made red by trauma, cold, or heat. The paler area is due to the blood vessels within the area which are more sensitive to the body’s normal vasoconstricting chemicals.
Adrenergic urticaria is a skin condition characterized by an eruption consisting of small (1-5mm) red macules and papules with a pale halo, appearing within 10 to 15 min after emotional upset. There have been 10 cases described in medical literature, and involve a trigger followed by a rise in catecholamine and IgE. Treatment involves propranolol and trigger avoidance.
Jellyfish dermatitis is a cutaneous condition caused by stings from a jellyfish.
Cutaneous lymphoma, also known as lymphoma cutis, is when lymphoma involves the skin. It is characterized by a proliferation of lymphoid tissue.
Cutaneous manifestations of COVID-19 are characteristic signs or symptoms of the Coronavirus disease 2019 that occur in the skin. The American Academy of Dermatology reports that skin lesions such as morbilliform, pernio, urticaria, macular erythema, vesicular purpura, papulosquamous purpura and retiform purpura are seen in people with COVID-19. Pernio-like lesions were more common in mild disease while retiform purpura was seen only in critically ill patients. The major dermatologic patterns identified in individuals with COVID-19 are urticarial rash, confluent erythematous/morbilliform rash, papulovesicular exanthem, chilbain-like acral pattern, livedo reticularis and purpuric "vasculitic" pattern. Chilblains and Multisystem inflammatory syndrome in children are also cutaneous manifestations of COVID-19.
Autoimmune urticaria, also known as chronic autoimmune urticaria, is a type of chronic urticaria characterized by the presence of autoantibodies in the patient's immune system that target the body's own mast cells, leading to episodes of hives (urticaria). This immunologically distinct type of urticaria is considered autoimmune because the immune system, which normally protects the body from foreign organisms, mistakenly attacks the body's own cells, causing inflammation and other symptoms.