Dermatitis atópica canina y enfermedad alérgica de la piel

Qué podría notar

• Rascarse, lamerse, morderse o restregarse durante semanas, y cada vez más
• Lamerse y morderse las patas, con el pelo manchado de un color óxido por la saliva
• Piel roja y con picazón en las axilas, la ingle, la barriga y alrededor de los ojos, el hocico y las orejas
• Problemas de oído que vuelven una y otra vez: sacude la cabeza, se rasca las orejas, las orejas huelen mal o tienen cera
• Piel que se pone gruesa y oscura y pierde el pelo justo en las zonas donde más se rasca
• Picazón que empezó antes de los tres años de edad, o que vuelve en la misma época cada año
• Costras, granitos, o un olor grasoso y a humedad, que suele indicar una infección de la piel añadida
• Un perro que no logra descansar de noche, o que interrumpe la comida y el juego para rascarse
• Picazón que está presente todo el año, o picazón junto con heces blandas, vómito o gases: ese patrón hace sospechar alergia alimentaria, que se ve casi igual, es un diagnóstico distinto y solo se comprueba con una dieta de eliminación estricta

Estándar de atención

1. Find and remove flare factors, and treat secondary infection, before escalating drugs

   Aprobado / respaldado por guías

   ICADA's first move for an acute flare is to search for and eliminate the cause of the flare, bathe with mild shampoos, and control pruritus and lesions with topical and/or oral glucocorticoids or oclacitinib. For chronic disease the first steps in management are identification and avoidance of flare factors plus adequate skin and coat hygiene. In practice that means year-round flea control, treating staphylococcal pyoderma, Malassezia dermatitis and otitis found on cytology, and not immunosuppressing an undiagnosed itch. THE FLEA-CONTROL STEP HAS A CROSS-SPECIES HAZARD ATTACHED. Concentrated permethrin and other pyrethroid dog spot-ons are severely and often fatally toxic to cats, including by secondary contact from a treated dog. In an Australian survey of 255 veterinary practices, 750 individual cases of permethrin spot-on intoxication in cats were reported over two years with 166 deaths, and the majority of cases involved products labelled for DOGS, applied to a cat accidentally or intentionally, or transferred by contact with a treated dog (Malik R et al., J Feline Med Surg 2010;12(1):5-14, PMID 20123482, DOI 10.1016/j.jfms.2009.12.002). In a multi-species household, the flea plan must be written for every animal in it.

   Productos nombrados: Topical antiseptics and mild shampoos; systemic or topical antimicrobials chosen on cytology and, where indicated, culture. Antimicrobial choice should be stewardship-aligned; no specific antibacterial is guideline-mandated for cAD, and repeated empirical long courses without cytology or culture select for methicillin-resistant Staphylococcus pseudintermedius. SAFETY LIMITS: never apply a dog ectoparasiticide to a cat, and keep a cat away from a freshly treated dog until the application site is dry; read the species statement on every flea product every time. Medicated shampoos and antiseptics are for the coat, not the eyes or ear canals, and a dog that licks a treated coat gets an oral dose.

   ICADA 2015 consensus treatment guidelines (Olivry et al.), with the diagnostic work-up specified in the companion ICADA diagnostic guidelines (Hensel et al. 2015, PMID 26260508, DOI 10.1186/s12917-015-0515-5). Consensus guideline, not an RCT. The pyrethroid-in-cats hazard is a practitioner survey with self-reported case counts (Malik 2010, PMID 20123482), so the counts are indicative rather than incidence, but the toxicity itself and the dog-product-on-a-cat route are not in question.

   Olivry T et al. BMC Vet Res 2015;11:210. PMID 26276051. DOI 10.1186/s12917-015-0514-6; Malik R et al. J Feline Med Surg 2010;12(1):5-14. PMID 20123482. DOI 10.1016/j.jfms.2009.12.002

2. Control the acute flare: topical or oral glucocorticoids, or oclacitinib

   Aprobado / respaldado por guías

   For an acute flare ICADA recommends controlling pruritus and lesions with topical and/or oral glucocorticoids or oclacitinib, alongside bathing. Oclacitinib is a Janus kinase inhibitor given orally and is FDA-approved for dogs (NADA 141-345). Expect rapid relief and use the flare course as the shortest effective course, not as the long-term plan. Owners must be told to call the clinic before changing an oclacitinib or steroid dose at home — the twice-daily induction period is deliberately short, and the common owner error is to keep the twice-daily rate going because it worked.

   Productos nombrados: Oclacitinib maleate (Apoquel, oral JAK inhibitor, FDA-approved for dogs, NADA 141-345 — verified on the DailyMed label). LABEL LIMITS, verbatim from that label: 'APOQUEL is not for use in dogs less than 12 months of age'; 'APOQUEL is not for use in dogs with serious infections'; 'APOQUEL may increase susceptibility to infection, including demodicosis, and exacerbation of neoplastic conditions'; 'New neoplastic conditions (benign and malignant) were observed in dogs treated with APOQUEL during clinical studies'; 'APOQUEL is not for use in breeding dogs, or pregnant or lactating bitches'; 'Dogs receiving APOQUEL should be monitored for the development of infections, including demodicosis, and neoplasia.' Human handling, verbatim: 'Wash hands immediately after handling the tablets… In case of accidental ingestion, seek medical attention immediately.' Oral glucocorticoids: prednisolone, methylprednisolone — expect increased thirst, urination and appetite, and panting; the risks that matter are iatrogenic hyperadrenocorticism, urinary tract infection and diabetes mellitus on prolonged use, so these are flare drugs on the shortest effective course. Topical glucocorticoids including hydrocortisone aceponate spray, and topical triamcinolone — use on defined areas for defined periods, not indefinitely over large areas. Topical tacrolimus is used OFF-LABEL in dogs: no veterinary label governs it, owners should wear gloves to apply it, the dog must be kept from licking the site, and the human topical tacrolimus product carries a boxed warning headed 'WARNING: Long-term Safety of Topical Calcineurin Inhibitors Has Not Been Established' which states that 'rare cases of malignancy (e.g., skin and lymphoma) have been reported in patients treated with topical calcineurin inhibitors, including tacrolimus ointment' (DailyMed, tacrolimus ointment). NEVER substitute a human oral or topical pain or anti-inflammatory product for any of these.

   ICADA 2015 guideline recommendation. Independently, a Cochrane-method systematic review of 49 randomised controlled trials enrolling 2,126 dogs found evidence of efficacy for oral glucocorticoids (5 RCTs), topical triamcinolone (1 RCT) and topical tacrolimus (3 RCTs) in reducing pruritus and/or lesions of canine AD (Olivry et al., Vet Dermatol 2010;21:4–22, PMID 20187910, DOI 10.1111/j.1365-3164.2009.00784.x). Long-term oclacitinib data come from a 247-dog open-label compassionate-use study dosed up to 630 days: 63.9% of dogs had a ≥50% reduction in pruritus VAS and 66.4% in dermatitis VAS at day 90 — and the SAME abstract reports that 'Urinary tract infection/cystitis, vomiting, otitis, pyoderma and diarrhoea were the most frequently reported (>5% of dogs) abnormal clinical signs', with haematology and serum chemistry means remaining within reference ranges (Cosgrove et al., Vet Dermatol 2015;26:171–9, PMID 25688708, DOI 10.1111/vde.12194). The efficacy figures and the adverse-event list come from one manufacturer-sponsored, open-label source and must always travel together.

   Olivry T et al. BMC Vet Res 2015;11:210. PMID 26276051. DOI 10.1186/s12917-015-0514-6; Cosgrove SB et al. Vet Dermatol 2015;26(3):171-9, e35. PMID 25688708. DOI 10.1111/vde.12194

3. Establish long-term pruritus control with a guideline-listed agent

   Aprobado / respaldado por guías

   For chronic canine AD, ICADA states the medications currently most effective in reducing chronic pruritus and skin lesions are topical and oral glucocorticoids, oral ciclosporin, oral oclacitinib, and — where available — injectable recombinant interferons. Lokivetmab, a caninized anti-interleukin-31 monoclonal antibody given by subcutaneous injection, is the other mainstream long-term option and post-dates the 2015 guideline text. Lokivetmab relieves itch only: it has no antimicrobial activity and does not treat the secondary pyoderma, Malassezia dermatitis or otitis that often accompany a flare, so a dog that stops scratching on it can still have an untreated infection.

   Productos nombrados: Lokivetmab (Cytopoint) — a veterinary BIOLOGIC licensed by USDA APHIS Center for Veterinary Biologics in December 2016, NOT FDA-approved; EU marketing authorisation EMEA/V/C/003939, first authorised 5 May 2017 (verified on the EMA medicine page). LIMITS: it treats pruritus, not infection; anti-drug antibodies may develop; reported adverse effects include injection-site pain, lethargy, vomiting, diarrhoea, anorexia, hyperexcitability and urinary incontinence; like any injected protein it can in rare cases provoke an acute allergic reaction, so the emergency signs in the red-flag list apply for the hours after a dose. Ciclosporin (cyclosporine, modified, oral — Atopica) — FDA-approved for canine atopic dermatitis, NADA 141-218 (verified on the DailyMed label). LABEL LIMITS, verbatim: 'ATOPICA is contraindicated for use in dogs with a history of neoplasia. Do not use in dogs with a hypersensitivity to cyclosporine'; 'ATOPICA (cyclosporine) is a systemic immunosuppressant that may increase the susceptibility to infection and the development of neoplasia'; 'The safety and effectiveness of ATOPICA has not been established in dogs less than 6 months of age or less than 4 lbs body weight'; 'Killed vaccines are recommended for dogs receiving ATOPICA because the impact of cyclosporine on the immune response to modified live vaccines is unknown.' Label adverse reactions include vomiting 30.9%, diarrhoea 20.0%, persistent otitis externa 6.8%, gingival hyperplasia 2.3% ('Gingival hyperplasia regressed with dose tapering') and lymphadenopathy 2.3%; owner handling, verbatim: 'Capsules should not be broken or opened. Wear gloves during administration.' Oclacitinib maleate (oral) — label limits as listed in the flare step above. Recombinant interferons are EU-market products and are not US-licensed for this use. REGULATORY DISCIPLINE: implying FDA approval for a USDA-licensed biologic, or the reverse, is a genuine compliance error — Cytopoint is USDA APHIS-licensed, Apoquel and Atopica are FDA-approved, and none of them is 'approved' unqualified.

   ICADA 2015 guideline. The systematic review of 49 RCTs / 2,126 dogs found evidence of efficacy for oral ciclosporin (6 RCTs) and subcutaneous recombinant gamma-interferon (1 RCT) (PMID 20187910). For lokivetmab the pivotal-class trial randomised 274 client-owned dogs with chronic AD across 40 European practices to monthly lokivetmab or daily oral ciclosporin: lokivetmab was NON-INFERIOR to ciclosporin for pruritus reduction at day 28 (51.90% vs 43.72%), onset was within one day, and in the 81-dog continuation phase 76.3% of assessed dogs were rated 'normal' for pruritus at study end. Honest caveat that must travel with this citation: non-inferiority for the CADESI-03 lesion endpoint was NOT achieved (54.17% vs 56.86%), and at no time point were mean CADESI-03 scores significantly different between groups. Moyaert et al., Vet Dermatol 2017;28:593–e145, PMID 28906040, DOI 10.1111/vde.12478 — manufacturer-authored. Real-world limits: in 135 referral dogs on lokivetmab, adverse effects (lethargy, vomiting, hyperexcitability, injection-site pain, urinary incontinence) were reported in 11 of 132 dogs, and dogs that had not responded to oclacitinib were LESS likely to respond to lokivetmab (Souza et al., Vet Dermatol 2018;29:489-e164, PMID 30141223, DOI 10.1111/vde.12682).

   Moyaert H et al. Vet Dermatol 2017;28(6):593-e145. PMID 28906040. DOI 10.1111/vde.12478; Souza CP et al. Vet Dermatol 2018;29(6):489-e164. PMID 30141223. DOI 10.1111/vde.12682

4. Offer allergen-specific immunotherapy — the only disease-modifying option

   Aprobado / respaldado por guías

   ICADA states that allergen-specific immunotherapy and proactive intermittent topical glucocorticoid application are the ONLY interventions likely to prevent or delay the recurrence of flares. Everything else on this page controls signs. ASIT requires a confirmed clinical diagnosis of cAD first, then allergy testing to select the allergens, then months of subcutaneous or sublingual dosing before a verdict. It is an injection of the very allergens the dog reacts to, so the induction doses belong where the dog can be watched afterwards, and an owner who gives maintenance injections at home must have the emergency signs, a plan, and a phone number — and must never adjust the volume or the interval without calling first.

   Productos nombrados: Allergen extracts are compounded per patient from the test-identified allergens; there is no single named approved product to cite. Route is subcutaneous or sublingual. LIMITS: months before a verdict, no benefit from testing without a clinical diagnosis first, uncommon and usually mild adverse effects under supervision, and an acute allergic reaction is the one that must be recognised — observe the dog after induction doses, and call before any dose or interval is changed at home.

   ICADA 2015 consensus statement, verbatim on the prevention point. Supported independently by the Cochrane-method systematic review, which found evidence of efficacy for subcutaneous allergen-specific immunotherapy in 3 randomised controlled trials within a body of 49 RCTs / 2,126 dogs (Olivry et al., Vet Dermatol 2010;21:4–22, PMID 20187910). Allergen selection methodology is specified in the ICADA diagnostic guidelines (Hensel et al. 2015, PMID 26260508). SAFETY, stated rather than assumed: in a retrospective series of 230 client-owned dogs given supervised rush immunotherapy, adverse effects occurred in 6 of 230 (2.6%) — five with mild gastrointestinal signs and one with a 1.5 °C temperature rise — and all were graded mild and self-limiting (Weitzer T, Mueller R, Vet Dermatol 2023;34(5):385-392, PMID 37157908, DOI 10.1111/vde.13170). In 82 dogs on venom immunotherapy, 26 had at least one adverse event, the per-injection reaction rate was 2.8%, gastrointestinal upset was the most common event, and 'No deaths or severe anaphylactic reactions were reported' (Ewing TS et al., Vet Dermatol 2021;33(1):40-e14, PMID 34414617, DOI 10.1111/vde.13016). So the defensible statement is that reactions are uncommon and usually mild under supervision — not that they cannot happen, and not that anaphylaxis is documented at any measurable rate in these canine series.

   Olivry T et al. BMC Vet Res 2015;11:210. PMID 26276051. DOI 10.1186/s12917-015-0514-6; Weitzer T, Mueller R. Vet Dermatol 2023;34(5):385-392. PMID 37157908. DOI 10.1111/vde.13170

5. Add proactive intermittent topical glucocorticoid to previously affected sites

   Aprobado / respaldado por guías

   Rather than waiting for the next flare, the guideline supports applying topical glucocorticoid intermittently to the sites that flare, as a flare-prevention strategy. It is the second of only two interventions ICADA credits with preventing or delaying recurrence, and it is cheap. Because this step deliberately makes a steroid a LONG-TERM habit, it has to be prescribed with its own ceiling: named sites, a named frequency, a named review date, and a veterinary skin check at that review. Chronic topical glucocorticoid use thins skin, and the changes to look for at review are thinning or transparency of the treated skin, new comedones ('blackheads'), visible surface blood vessels, easy bruising, poor wound healing, delayed hair regrowth, and firm gritty plaques suggesting calcinosis cutis. Topical steroid is also absorbed: a large treated area, an occluded fold, or a dog that licks the site can produce systemic steroid effects including increased thirst and urination. Owners should never extend the treated area, increase the frequency, or start a human hydrocortisone or combination cream on their own — call first.

   Productos nombrados: Hydrocortisone aceponate spray and other veterinary topical glucocorticoids; topical triamcinolone. LIMITS: defined sites, defined frequency, a scheduled skin review; watch for skin thinning, comedones, visible vessels, bruising, poor healing and firm gritty plaques; expect some systemic absorption over large or occluded areas; keep the dog from licking treated skin. Human hydrocortisone and human combination steroid creams are not a substitute and must not be started by an owner.

   ICADA 2015 consensus statement, stated explicitly alongside ASIT as the only two flare-prevention interventions. Topical glucocorticoid efficacy for active disease is separately supported by a topical triamcinolone RCT within the 49-RCT systematic review (PMID 20187910). HONESTY NOTE ON THE HARM LIST: the cutaneous-atrophy, comedone and calcinosis-cutis effects of prolonged topical glucocorticoid use are the standard veterinary dermatology caution and are the reason the guideline says intermittent rather than continuous, but a primary citation quantifying them in dogs on a proactive intermittent protocol was NOT captured in this research pass. They are therefore written here as what to monitor and discuss with the prescribing veterinarian, not as a cited incidence.

   Olivry T et al. BMC Vet Res 2015;11:210. PMID 26276051. DOI 10.1186/s12917-015-0514-6

6. Build the skin-barrier and hygiene layer: bathing frequency and essential fatty acids

   Ensayo controlado en esta especie

   ICADA's chronic-disease algorithm asks for adequate skin and coat hygiene, which might include more frequent bathing and possibly increasing essential fatty acid intake. This is adjunctive and slow, and its best-documented value is drug-sparing rather than standalone itch control.

   Productos nombrados: Omega-3 / essential fatty acid supplements and EFA-enriched diets; mild non-irritant shampoos. No FDA-approved drug claim attaches to these. LIMITS: high-dose fish oil can cause loose stool and, at high intakes, affects platelet function, so it is a dose to agree with the veterinarian rather than to escalate at home — and an oil-flavoured supplement will break an elimination diet trial. Human medicated shampoos, dips and 'anti-itch' products are not interchangeable with veterinary ones.

   The systematic review of 49 RCTs reports that one HIGH-QUALITY randomised controlled trial showed an oral essential fatty acid supplement could reduce prednisolone consumption by approximately half (Olivry et al., Vet Dermatol 2010;21:4–22, PMID 20187910, DOI 10.1111/j.1365-3164.2009.00784.x). A 23-study systematic review found omega-3 benefit across indications including allergic dermatitis and haircoat (Magalhães et al., In Vivo 2021, PMID 33910819, DOI 10.21873/invivo.12394). Do not present fatty acids as a substitute for the agents in the steps above.

   Olivry T et al. Vet Dermatol 2010;21:4–22. PMID 20187910. DOI 10.1111/j.1365-3164.2009.00784.x

7. Measure response, and monitor the drug as well as the disease, on a schedule

   Aprobado / respaldado por guías

   cAD is a relapsing-remitting disease with strong seasonal and placebo components, so before-and-after impressions are unreliable. Score owner-reported itch and veterinarian-observed lesions at every decision point, and re-check at dose changes and at seasonal onset. A dog on long-term immunomodulation needs its own monitoring loop alongside the itch score: recheck examination looking specifically for new infection, demodicosis, a new lump, and in glucocorticoid patients for polyuria/polydipsia and urinary tract infection; and repeat the baseline bloodwork rather than treating it as a one-off. The Apoquel label directs that dogs receiving it 'should be monitored for the development of infections, including demodicosis, and neoplasia', and the Atopica label warns of increased susceptibility to infection and development of neoplasia — those are monitoring instructions, not background text. Set the interval with the prescribing veterinarian, write it in the record, and hold to it even while the dog looks well.

   Productos nombrados: Not applicable — this step is measurement and drug monitoring, not medication. It exists so that the label monitoring requirements for oclacitinib and ciclosporin actually get performed.

   The owner-scored pruritus Visual Analog Scale was validated in 713 owners, establishing a normal range of 0–1.9 and a median post-treatment reduction of 4.4 points; notably only 12% of owners would have been satisfied with the 50% reduction typically quoted as success in antipruritic drug trials (Rybnícek et al., Vet Dermatol 2009;20:115–22, PMID 19171021, DOI 10.1111/j.1365-3164.2008.00728.x). CADESI-4 is the ICADA-recommended lesion scale, scoring erythema, lichenification and alopecia/excoriation 0–3 at 20 body sites, with severity benchmarks of 10 (mild), 35 (moderate) and 60 (severe) (Olivry et al., Vet Dermatol 2014;25:77–85, PMID 24461108, DOI 10.1111/vde.12107). The drug-monitoring instructions are label text from DailyMed for Apoquel (NADA 141-345) and Atopica (NADA 141-218); the 630-day oclacitinib study re-assessed at approximately 90-day intervals and found haematology and serum chemistry means within reference ranges over that period (Cosgrove et al. 2015, PMID 25688708). No specific numeric recheck interval for canine AD immunomodulation is set by the ICADA guideline, so the interval is a prescriber decision and is not asserted here as a guideline requirement.

   Rybnícek J et al. Vet Dermatol 2009;20(2):115–22. PMID 19171021. DOI 10.1111/j.1365-3164.2008.00728.x; Olivry T et al. Vet Dermatol 2014;25(2):77–85. PMID 24461108. DOI 10.1111/vde.12107

Cómo se diagnostica

• Establish the clinical diagnosis by pattern, not by a test. ICADA's diagnostic guidelines are explicit: cAD is diagnosed by meeting clinical criteria and ruling out other causes with similar signs (Hensel et al., BMC Vet Res 2015;11:196, PMID 26260508, DOI 10.1186/s12917-015-0515-5).
• Rule out ectoparasites. Flea combing and deep skin scrapings for Demodex and Sarcoptes are specified in the guideline work-up; add a therapeutic acaricidal trial where scabies remains plausible, since scrapings are insensitive (Hensel 2015, PMID 26260508).
• Cytology of skin and ear canal for staphylococcal and Malassezia overgrowth, and treat what you find before judging any antipruritic. Uncontrolled secondary infection is the most common reason an atopic dog 'fails' a drug (Hensel 2015, PMID 26260508).
• Culture and susceptibility, not another empirical course, when pyoderma recurs or fails. Repeated long empirical systemic antibiotic courses without cytology and, on recurrence or failure, culture, are how methicillin-resistant Staphylococcus pseudintermedius is selected for in this exact patient population. Topical antisepsis carries much of this work and should be used before and alongside systemic drugs, not after them.
• Run an elimination diet trial in any dog with perennial pruritus and/or concurrent gastrointestinal signs. The guideline states this is required, not optional, in that subgroup (Hensel 2015, PMID 26260508). Tell the owner in plain words what the trial is: a single prescribed diet, commonly for about eight weeks, with nothing else entering the dog — no treats, no table food, no dental chews, no flavored medicines or flavored preventives — followed by re-challenge. Cutaneous adverse food reaction is a separate diagnosis that looks nearly identical to environmental atopic dermatitis, and a trial that is 95% strict is a trial that produces no answer.
• Only after cAD is clinically diagnosed, perform allergy testing — intradermal testing or allergen-specific serum IgE — to identify candidate allergens for allergen-specific immunotherapy. It is an allergen-selection tool, not a diagnostic test (Hensel 2015, PMID 26260508). Interpret serology conservatively: 75.6% of 25,451 dogs with merely suspected cAD were IgE-positive to at least one allergen (Drouet et al. 2024, PMID 39469743).
• Record a baseline owner-scored pruritus VAS and a baseline veterinarian-scored CADESI-4 before starting therapy, so response is measured rather than remembered (Rybnícek et al. 2009, PMID 19171021; Olivry et al. 2014, PMID 24461108).
• Obtain baseline CBC and serum chemistry, and urinalysis where a glucocorticoid or another immunomodulator is planned, before starting long-term immunomodulation — then repeat them on a schedule rather than once. Document flea/tick preventive coverage and bathing frequency, both of which are guideline-level flare factors (Olivry et al. 2015, PMID 26276051). Record which other animals live in the household and which species they are, because the flea-control plan you write for the dog can kill a cat.