(Adnkronos) - "E’ un mondo eterogeneo e complesso quello dell’orticaria da affrontare sempre con grande cura ed attenzione, potendo l’orticaria essere la manifestazione esterna e visibile di una condizione patologica, d’organo o sistemica, che cova silenziosamente senza dare segni macroscopicamente apprezzabili. Certo, diversi casi di orticaria sono provocati da reazioni allergiche, per quanto gli agenti scatenanti possano essere molteplici: farmaci, alimenti, pollini, acari, peli e forfore animali, spore fungine, sostanze chimiche come farmaci o mezzi di contrasto o veleno di insetti o contatti con erbe urticanti". Alle orticarie è dedicata la nuova puntata della rubrica τροφήν, la prima Medicina curata dall’immunologo Mauro Minelli, docente di dietetica e nutrizione umana presso l’Università LUM di Bari. "Alcuni pazienti rispondono bene alla terapia antistaminica, altri possono richiedere un trattamento cortisonico - spiega l'immunologo - Nei casi più complessi vi sono segnalazioni sull’utilizzo di farmaci biologici. In altri studi pubblicati sono stati presi in esame pazienti con orticaria cronica e livelli di D-dimero elevati, nei quali l’utilizzo di anticoagulanti sembra aver dato buoni risultati. Ed ancora ci sono casi di orticaria secondaria a patologie focali (granulomi dentari), casi di orticaria in pazienti con infezioni come quella da Helicobacter pylori con una discreta percentuale di remissione dell’orticaria dopo terapia eradicante. E poi ci sono le orticarie causate da parassiti (elminti, ossiuri, anisakis) e quelle che possono conseguire a traumi fisici, all’azione di additivi, coloranti, ad intense condizioni di stress emotivo o anche ad un’attivazione non immunologica del complemento". "Sul versante clinico le orticarie, che quando regrediscono entro sei settimane dall’esordio vengono definite 'acute', sono caratterizzate dall’improvvisa comparsa di ‘pomfi’ variabili per numero e sede. Si tratta di eruzioni rosse e pruriginose, fugaci, di diverse forme e di dimensioni variabili da pochi millimetri ad alcuni centimetri di diametro. Generalmente i pomfi si presentano in forma rotondeggiante, oppure sotto forma di anelli e chiazze di grandi dimensioni. Di solito - rimarca - scompaiono più o meno rapidamente per poi ricomparire, a gittate successive, accompagnati da prurito, in diverse sedi corporee. In alcuni casi, su palpebre, padiglioni auricolari, organi genitali, mani, piedi, insieme ai pomfi può coesistere un gonfiore dei tessuti (angioedema) che è poco o niente pruriginoso ma spesso doloroso. Talvolta all’orticaria estesa si possono associare manifestazioni sistemiche di tipo cardiovascolare (ipotensione fino allo shock), respiratorio (dispnea, tosse) o gastroenterico (dolori addominali, diarrea, vomito)". "In alcuni casi di orticaria cronica può anche essere utile esplorare la tiroide, considerando che gli ormoni tiroidei tetra-iodotironina o tiroxina (T4) e tri-iodotironina (T3) giocano un ruolo importante anche nel mantenere le normali funzioni della pelle, in particolare il consumo di ossigeno, la sintesi proteica, le mitosi, lo spessore cutaneo, la crescita dei capelli e una normale secrezione di sebo. Ne consegue - osserva Minelli - che eventuali alterazioni della cute e dei suoi annessi potrebbero essere associate a malfunzionamenti della tiroide ed in particolare ad un ipertiroidismo ovvero ad un ipotiroidismo magari dovuti a malattie autoimmuni a carico della ghiandola". "Ad un quadro acuto o cronico di orticaria, pertanto, sarà sempre il caso di accostarsi con approccio il più possibile aperto ad opzioni cliniche allargate, provando ove possibile a superare il concetto spesso limitativo delle forme definite 'idiopatiche' e, comunque, sempre diffidando ed escludendo il ricorso inconcludente alle iniziative taroccate dei test di intolleranza sconclusionati e farlocchi", conclude.
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00:00Orticaria is a pathology characterized by the more or less sudden appearance of cutaneous eruptions, called pomphies,
00:19which are nothing more than irregular and reddened inflations that appear on the surface of the cutae and which are usually associated with a more or less intense sensation of pruritus.
00:32Orticaria can affect any area of the epidermis and sometimes it can also involve deeper layers of the cutae.
00:41We will talk in this case of angioedema, which is an accumulation of liquid in the soft tissues, especially of the face, in particular the palpebrae, the lips, sometimes the tongue, sometimes the throat, or the auricular patellae or the genital organs.
00:57In this case, in fact, we are talking about angioedema or orthicare angioedema syndrome in the case in which both the pomphies and the edema should manifest at the same time.
01:09So, from the point of view of duration, the orticarii can be distinguished into acute orticarii, those that extinguish in the time frame of a maximum of six weeks, or otherwise we will talk about chronic orticarii.
01:25Chronic orticarii, let's say, represents 25-30% of all forms of orticarii. It seems to interest, above all, people of middle age and, in particular, people of female gender, with a male-female ratio equal to 3 to 1.
01:44Now, every time we talk about orticarii, the thought immediately runs to allergies. In fact, it is true, orticarii can manifest in subjects that have already documented a form of allergic sensitization to acaries, pollen, moths, animal epithelium, lactic acid, nickel.
02:06Certainly yes, but it is not said that orticarii must necessarily respond to allergological logic, in the sense that orticarii, especially if chronic, can also manifest for a series of events, always immunological but not allergological.
02:27I am referring above all to autoimmune diseases, in which some pathological auto-antibodies, with particularly complex mechanisms, activate what are the main cells of the orticarium, that is, the mastocytes, which are the real deposits of the stamina.
02:48Now, what happens? It happens that once stimulated, once activated, these mastocytes go against degranulation, that is, the membrane that delimits this cellular element breaks and granules of histamine come out of the cell.
03:05Histamine and histamine, together with other mediators that are released in this particular process, are responsible for the physiopathological modifications that are at the base of the orticarium.
03:20I remind you that histamine is able to generate vasodilation, therefore it produces heat, reddening, edema of the area of interest and then, as it also stimulates the nerve sensory fibers, it can generate pruritus or pain.
03:35So, we can say that the orticarium is certainly a complex pathology, very heterogeneous, which can respond to allergological logics, we said, but also not, which responds in a different way to drugs.
03:51In the sense that there are people with chronic orticarium who respond well to only antihistamine therapy, other people who instead must associate antihistamine therapy with cortisone, but the approach is also different depending on the therapeutic approach to the orticarium.
04:09In the sense that in some cases of vascular orticarium, for example, an elevated value of dimer is found in the blood of these subjects. In this case, anticoagulant therapy will work well.
04:21Other times, the orticarium is associated with an infection by Helicobacter pylori, so much so that an eradicating therapy seems to be able to stabilize the orticarium, but we remember that in the intestinal microbiota there is not only Helicobacter pylori.
04:38Other pathogenic bacteria, possibly in excess in the intestinal microbiota of a patient with orticarium, could release their metabolites, such as lipopolysaccharide, capable of generating vasculate, vasculate orticarium and therefore become responsible for orticarium.
04:56As if to say that the assessment of Helicobacter pylori alone is not enough to understand some forms of orticarium that are sometimes incomprehensible. Orticarium can also depend on chemical substances, for example drugs, for example contrasting agents, for example poisons such as insect poison.
05:14Orticarium can also depend on parasites, in the case of Elminti, Ossiuri and Anisakis. Orticarium can also depend on local inflammatory foci, such as dental granulomas. Orticarium can also depend on intense emotional stress, on particularly intense stress-inducing events.
05:36And then there is the great chapter of food, in the sense that many foods can become responsible for orticarium forms. Now, there may be an allergy to food, there may be an allergy to some foods, in the sense that there are subjects who, just as they are allergic to dust, mold or cat's epithelium, may also be allergic, I don't know, to milk proteins or egg proteins.
06:02In this case, eating those foods, these people go against orticarium. Or there are subjects allergic to nickel, who are allergic not to food, but to nickel, which is contained in the food, which, coming from the ground, may have recovered nickel from the ground.
06:20Or there are subjects who have cross-reactions, that is, they are allergic not to a certain food, but to an antigen, to a molecular fraction, which is contained, for example, in some external agents and in foods. A particular example is lactic acid.
06:38Subjects allergic to some lactic molecules can become allergic, for example, if they eat avocado or if they eat peach or apricot or grape or figs or pineapple. So there are these forms of cross-reactions that must certainly be identified.
06:54Subjects allergic to dust can become orticarium, for example, if they eat crustaceans, if they eat shrimp, if they eat scampi, if they eat elastic lobster. And this is because between dust and these crustaceans there is a protein that is common to both.
07:11Therefore, the intake of foods that contain that protein can evoke orticarium. But there are also foods in which the subject has no type of allergy. And these foods are able to evoke the release of histamine from mastocytes, of which I spoke previously, not with allergic mechanisms, but for a direct damage action that those foods are able to perform on the mastocyte.
07:39In this case we speak of PAR, that is, of pseudo-allergic reactions determined by foods called liberatory or degrading histamine. Examples? Chocolate, dried fruit, strawberries, egg whites, fish, crustaceans, fermented drinks, fermented or seasoned cheeses.
08:01I remind you and conclude that there is no allergy to these foods and that those foods will stop generating orticarium when the responsible cell, that is, the mastocyte, regains its stability that it had previously lost.
08:20So a complex field, that of orticarium, a field that requires competence and that certainly should not be faced with tricks or tests by the eye.