Contributors: David Godfrey, Rosanna Marsella, Richard Squires

 Species: Canine   |   Classification: Diseases

Introduction Pathogenesis Diagnosis Treatment Outcomes Further Reading


  • Cause: inherited predisposition to develop hypersensitivity-mediated skin disease against environmental allergens.
  • Signs: pruritic skin disease (may be seasonal), recurrent skin and ear infections.
  • Diagnosis: suggestive history, compatible clinical signs and exclusion of other pruritic skin diseases.
  • Treatment: desensitization or symptomatic management.
  • Prognosis: guarded - problems likely to persist lifelong.
    Print off the owner factsheet on Atopy Atopy to give to your client.

Presenting Signs

  • Pruritus affecting the face, feet, pinnae, ventral abdomen and axillae; usually sparing the dorsum.
  • Advanced cases show lesions of self-trauma (saliva staining on hairs, excoriation, hair loss, hyperpigmentation, and lichenification).
  • Chronically relapsing skin infections.

Geographic Incidence

  • Atopy is universally recognized, probably affecting 10% of canine population.

Age Predisposition

  • Signs are expected to start between 6 months and 2 years of age and often worsen as the dog matures.
  • Significant numbers of affected dogs only have serious signs when older but have had milder signs when young.
  • They will usually persist for life.

Breed Predisposition

  • Breed predispositions seems to vary according to populations and geography. The following breeds have been suggested to be predisposed by studies that have included a control group.

Cost Considerations

  • Very variable according to severity and seasonality of the signs and the ability of the owner to perform some cheaper treatments such as washing.
  • The diagnostic protocol can be lengthy and expensive.
  • Needs life-long management regimes which may be costly.
  • In dogs with seasonal pruritus, inexpensive treatment will often control the problem.



  • Unknown: thought in part to be associated with dysregulation of cytokine production and alterations in T-cell subset populations.
  • Abnormal epidermal integrity is also probably important.

Predisposing Factors

  • Familial history of atopy.
  • Some studies show a link between month of birth and development of atopy. Dogs born during the pollen season may become sensitized in the first few months of life.
  • Parasites may increase the dog's production of IgE to other environmental allergens.
  • Viral infection or vaccination also increase production of IgE to environmental allergen.
  • Being raised in a rural environment may protect against the development of atopic dermatitis.


  • Still poorly understood. There seems to be both epithelial barrier function and immunological abnormalities.
  • There is an imbalance in T-cell populations and aberrant cytokine production.
  • Antigen-presenting cells stimulate the production of T helper 2 cells both locally and at distant lymph nodes → stimulate IgE-producing B cells, producing interleukins → mast cell and eosinophil.
  • Mast cell degranulation releases vasoactive factors → start of the inflammatory cascade.
  • The corneocytes of atopic dogs have greater adherence for Staphylococcus pseudintermedius Staphylococcus intermedius , → the high frequency of development of secondary pyoderma Skin: bacterial skin disease - overview.
  • A defective epidermal barrier allows percutaneous absorption of allergen. The allergen contacts allergen specific IgE on Langerhans' cells. Allergens are trapped, processed, and presented to allergen specific T lymphocytes. This results in increased numbers of T helper 2 cells which produce interleukins. Ultimately, there is enhanced production of allergen specific IgE by B lymphocytes.


  • Indoor allergens appear important throughout the world:
    • House dust mites - Dermatophagoides farina, D. pteronysinus and possibly Blomia tropicalis and Euroglyphyus maynei.
    • Storage mites - Acarus siro, Tyrophagus putrescentiae and Lepidoglyphus destructor are of less certain signifcance.
  • Pollens are important in Australia and North America and may be less commonly important in Europe.
  • Molds are uncommonly important allergens.
  • Malassezia is sometimes used in immunotherapy.
  • Danders from other mammals, and bird feather allergens are sometimes included.


  • Disease is uncommon <6 months of age (except in Shar Pei - seen earlier).
  • Signs worsen with age.
  • Disease that starts seasonally often becomes year round.
  • Secondary pyoderma or Malassezia Skin: malassezia disease disease is often a significant part of disease.


Presenting Problems

Client History

  • Pruritus is expected in skin allergies.
  • Foot licking.
  • Face rubbing.
  • Licking and scratching at abdomen.
  • Head-shaking and ear scratching.
  • Recurrent dermatitis since a young age. Onset up to 3 years.
  • Seasonal recurrence - may be associated with increased indoor activity (in the case of house dust mite allergy) or outdoor activity (where there is allergy to pollens).
    Some pollen-allergic patients show non-seasonal signs because of multiple allergies to plants with different pollination periods.
  • Recurrent otitis.
  • Hair loss, especially ventrally.
  • Familial history of atopy +/- a breed predisposition.
  • Irregular estrous cycles, low conception rates and false pregnancy Pseudopregnancy (false pregnancy or pseudocyesis). have not been proven to be associated with atopy.

Clinical Signs

  • Diagnosis is clinical and by exclusion of other pruritic skin diseases.
  • Facial erythema and pruritus Atopy peri-orbital.
  • Pedal erythema and pruritus Atopy extremities.
  • Ventral erythema Atopy chronic - groin.
  • Secondary staphylococcal pyoderma Pyoderma metatarsus.
  • Pinnal erythema.
  • Lichenification of the flexor surface of the tarsal joint and/or the extensor surface of the carpal joint Lichenification.
  • Chronic or chronically relapsing dermatitis.
  • Salivary staining of coat.
  • Otitis externa Otitis externa chronic - Cocker Spaniel.
  • Hyperhidrosis.
  • Conjunctivitis.
  • Lichenification Lichenification.
  • Alopecia.
  • Rhinitis.
  • Asthma.
    The severity of clinical signs may be recorded using a scoring system. Various systems of different complexity have been described, the latest being CADESI-4.
  • It is important to distinguish between acute and chronic atopic dermatitis as they have different interventions Skin: atopy - anti-inflammatory therapy:
    • Acute disease is shown by puritus, erythema and excoriation.
    • Chronic disease also has lichenification and often secondary bacterial and/or Malassezia dermatitis.

Diagnostic Investigation


  • To help rule out parasitic differentials.
  • To help rule out primary microbial infections - bacteria or yeasts and to identify secondary complications of atopic dermatitis.


  • Culture Bacteriology:
    • Skin swabs for culture to identify and allow control of bacterial infection if identified by cytology and if antibiotic treatment is being contemplated.
    • Culture without prior or concurrent cytology is very difficult to interpret as positive cultures will be found sampling normal skin.


Allergy testing Allergy testing is not used to diagnose or rule out atopic dermatitis, rather it is used once a diagnosis has been established and to aid treatment - allergen avoidance or ASIT.
  • Corticosteroid administration should usually be withdrawn BEFORE allergy testing as this gives greater confidence that a negative test is a true negative - advice should be sought from the dermatologist or laboratory running the test but withdrawal periods range from 14-90 days depending on product used.
  • Other than progestagens no other agents affect serological allergy testing:
    • Ciclosporin does not need withdrawal.
    • Oclacitnib use for 2 weeks does not require withdrawal but longer treatment periods have not been evaluated for their effects on allergy testing. Antihistamines must be withdrawn for 2 weeks prior to intradermal testing.
    • Lokivetmab Lokivetmab does not need to be withdrawn.

Histopathology Findings

  • Histopathology is not useful in positively diagnosing atopic dermatitis and skin biopsy is not part of an "allergy work up".
  • It may be useful in ruling out other differentials.
  • It may be useful to diagnose pyoderma or Malassezia infection but this usually is better done in other ways, eg cytology.
  • Superficial perivascular dermatitis, lymphocytes and histiocytes predominate in skin allergy but are non-specific.

Differential Diagnosis



Standard Treatment

  • Using evidence-based veterinary medicine, studies have shown benefits of systemic steroids and ciclosporin, topical tacrolimus Tacrolimus , oclacitinib Oclacitinib and lokivetmab.
  • See Skin: atopy - anti-inflammatory therapy Skin: atopy - anti-inflammatory therapy Anti-inflammatory treatment options.
  • There is weaker evidence supporting the use of ASIT, topical trimancinolone Triamcinolone spray, oral pentoxifylline Pentoxifylline, gamma interferon Interferon and oral misoprostol Misoprostol. These last 3 treatments are not routinely used currently.
  • The International Task Force on Veterinary Dermatology (now International Committee on Allergic Diseases of Animals, ICADA) has recommended that most dogs should have immunotherapy unless their signs are mild or restricted to a short season. This is because it is the only treatment that can resolve the problem rather than hide the clinical signs.
  • Control secondary bacterial infections - usually using topical antiseptics but systemic antibiotics chosen after cytology and culture and sensitivity are sometimes needed.
  • Control of secondary Malassezia infection may be necessary long-term in some dogs, both topical and systemic medications are useful.
  • Address concurrent allergies, ie adverse reaction to food or flea bite hypersensitivity.
  • Allergen avoidance has a small part to play in management of atopic dogs Skin: atopy - allergen avoidance.
  • Antihistamines Therapeutics: skin are probably variably effective. There are actually no scientific studies that support their use but they are favored for long-term control by some experienced owners of atopic dogs. Several may need to be tried in an individual. They are more effective in preventing pruritus than in initially bringing it under control and might be more helpful as a treatment to reduce the required dose of, eg systemic steroids.
  • Topical therapy is valuable in reducing the allergenic load on the skin, normalizing the skin barrier, soothing and reducing seconday infection. 
  • Leave-on conditioners with glucocorticoids are effective and do not suppress adrenal glands (not available in the UK).
  • Essential fatty acid supplementation Omega-3 fatty acids , enriched foods or application on to the skin have weak evidence to support their use. They have a low risk of side effects but can have a significant cost and might be more helpful as a treatment to reduce the required dose of, eg systemic steroids.


  • Monitoring response to treatment can be achieved both by the owner judging the level of pruritus at home and by the clinician judging the severity of skin lesions. The CADESI-4 score can be used by the clinician but it is very useful for clients to keep a pruritus diary and to record the level of pruritus each day, eg using a score out of 10 with 0-1 being normal and 10/10 being a constant itch. A similar score can be made using a Visual Analog Score (VAS) system - the owner places a mark on a 10 cm long line indicating the degree of itch.
  • Side-effects of glucocorticoid medication Prednisolone. Long-term use should prompt routine urinanalysis.
  • Avoidance of flare factors is vital, eg staphylococcal pyoderma, Malassezia or fleas.

Subsequent Management


  • See Skin: atopy - anti-inflammatory therapy Skin: atopy - anti-inflammatory therapy for details of using corticosteroids, oclacitinib, ciclosporin and tacrolimus.
  • Long-term use of antibacterial shampoos may result in secondary seborrhea necessitating changes of product or adding in a conditioner. 
  • Increase in itch should prompt search for flare factors - parasite infestation, bacterial infection or yeast infection.
  • Hyposensitization regimes may take up to 9 months to take effect.


  • Pruritus decreased.
  • Normalization of skin and haircoat.
  • Change in behavior so that the dog is more settled and "happier".



  • Good if seasonally affected; 90% can be satisfactorily controlled.
  • Many develop multiple allergies over succeeding years → increased difficulty in control.
  • Cost and time implications for owners of severely affected dogs may lead to requests for euthanasia.

Expected Response to Treatment

Reasons for Treatment Failure

  • Failure to diagnose concurrent disease, especially flea allergy, food sensitivity, pyoderma, Malassezia dermatitis.
  • Many cases become less responsive to glucocorticoids with the passage of time - frequently due to a failure to manage concurrent disease.
  • Inability of client to cope with treatment schedules.
  • Expense of those treatments with minimal side effects may lead to some owners having to use less effective and more dangerous interventions.

Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Olivry T, DeBoer DJ, Favrot C, Jackson HA, Mueller RS, Nuttall T, Prélaud P (2015) Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Veterinary Research 11, 210 BMC Vet Research.
  • Olivry T, Saridomichelakis M, Nuttall T et al (2014) Validation of the Canine Atopic Extent and Severity Index (CADESI)-4, a simplified severity scale for assessing skin lesions of atopic dermatitis in dogs.Vet Dermatol 25 (2), 77-85 PubMed.
  • Cosgrove S B, Wren J A, Cleaver D M et al (2013) A blinded, randomized, placebo-controlled trial of the efficacy and safety of the janus kinase inhibitor oclatinib (Apoquel) in client-owned dogs with atopic dermatitis. Vet Dermatol 24 (6), 587-597 PubMed.
  • Fleck T, Humphrey W, Coscarelli E (2013) Comparison of the janus kinase (JAK) inhibitor, oclacitinib, and prednisolone in canine models of pruritus. Vet Dermatol 23 (Suppl 1), 2-104 ScienceOpen.
  • Olivry T & Bizikova (2013) A systematic review of randomized controlled trials for prevention or treatment of atopic dermatitis in dogs: 2008-2011 update. Vet Dermatol 24 (1), 97-117 PubMed.
  • Favrot C, Steffan J, Seewald W & Picco F (2010) A prospective study on the clinical features of chronic canine atopic dermatitis and its diagnosis. Vet Dermatol 21 (1), 23-31 PubMed.
  • Olivry T (2010) New diagnostic criteria for canine atopic dermatitis. Vet Dermatol 21 (1), 123-126 PubMed.
  • Olivry T, Foster A P, Mueller R F et al (2010) Interventions for atopic dermatitis in dogs: a systemic review of randomized controlled trials. Vet Dermatol 21 (1), 4-22 PubMed.
  • Olivry T, DeBoer D J, Favrot C, Jackson H A, Mueller R S, Nuttall T & Prelaud P (2010) Treatment of canine atopic dermatitis: 2010 clinical practice guidelines from the International Task Force on Canine Atopic Dermatitis. Vet Dermatol 21 (3), 233-248 PubMed.
  • Nuttall T, Mueller R, Bensignor E et al (2009) Efficacy of a 0.0584% hydrocortisone aceponate spray in the management of canine atopic dermatitis: a randomized, double blind, placebo-controlled trial. Vet Dermatol 20 (3), 191-198 PubMed.
  • Nuttall T J, Hill P B, Bensignor E, Willemse T & the members of the International Task Force on Canine Atopic Dermatitis (2006) House dust and forage mite allergens and their role in human and canine atopic dermatitis. Vet Dermatol 17 (4), 223-235 PubMed.
  • Schnabl B, Bettenay S V, Dow K & Mueller R S (2006) Results of allergen-specific immunotherapy in 117 dogs with atopic dermatitis. Vet Rec 158 (3), 81-85 PubMed.
  • Steffan J, Favrot T & Mueller R (2006) A systematic review and meta-analysis of the efficacy and safety of cyclosporin for the treatment of atopic dermatitis in dogs. Vet Dermatol 17 (1), 3-16 PubMed.
  • Steffan J, Parks C, Seewald A & the North American Veterinary Dermatology Cyclosporine Study Group (2005) Clinical trial evaluating the efficacy and safety of cyclosporine in dogs with atopic dermatitis. JAVMA 226 (11), 1855-1863 PubMed.
  • Steffan J, Horn, J, Gruet P, Strehlau G, Fondati A, Ferrer L & Noli C (2004) Remission of the clinical signs of atopic dermatitis in dogs after cessation of treatment with cyclosporin A or methylprednisolone. Vet Rec 154 (22), 681-684 PubMed.
  • Olivry T, Mueller R S, The International Task Force on Canine Atopic Dermatitis (2003) Evidence-based veterinary dermatology: a systemic review of the pharmacology of canine atopic dermatitis. Vet Dermatol 14 (3), 121-146 PubMed.
  • Olivry T, Steffan J, Fisch R D, Prelaud P, Guaguere E, Fontaine J, Carlotti D N, European Veterinary Dermatology Cyclosporine Group (2002) Randomized controlled trial of the efficacy of cyclosporine in the treatment of atopic dermatitis in dogs. JAVMA 221 (3), 370-377 PubMed.
  • Fontaine J & Olivry T (2001) Treatment of canine atopic dermatitis with cyclosporine - a pilot clinical study. Vet Rec 148 (1), 662-663 PubMed.
  • Marsella R, Nicklin C F (2000) Double-blinded cross-over study on the efficacy of pentoxifylline for canine atopy. Vet Dermatol 11 (4), 255-260 VetMedResource.
  • Mueller R S, Bettenay S V & Tideman L (2000) Aero-allergens in canine atopic dermatitis in south-eastern Australia based on 1000 intradermal skin tests. Aust Vet J 78 (6), 392-399 VetMedResource.
  • Olivry T, Rivierre C, Jackson H A et al (2000) Cyclosporin A decreases skin lesions and pruritus in dogs with atopic dermatitis - a prednisolone controlled blinded trial. Vet Dermatol 13 (2), 77-87 PubMed.
  • Harvey R G (1999) A blinded, placebo-controlled study of the efficacy of borage seed oil and fish oil in the management of canine atopy. Vet Rec 155 (15), 405-407 PubMed.
  • Olivry T, Dean G A, Tompkins M B, Dow J L & Moore P F (1999) Toward a canine model of atopic dermatitis - amplification of cytokine-gene transcripts in the skin of atopic dogs. Exp Dermatol (3), 204-211 PubMed.
  • Scott D W & Miller W H (1999) Antihistamines in the management of allergic pruritus in dogs and cats. JSAP 40 (8), 359-364 PubMed.
  • Thomas R C, Logas D, Radosta L & Harrison J (1999) Effects of 1% hydrocortisone conditioner on haematological and biochemical parameters, adrenal function testing and cutaneous reactivity to histamine in normal and pruritic dogs. Vet Dermatol 10 (2), 109-116 VetMedResource.
  • Dérer M, Morrison-Smith G & de Weck A L (1998) Monoclonal anti IgE antibodies in the diagnosis of dog allergy. Vet Derm 9 (3), 185-190 VetMedResource.
  • Halliwell R E W, Gilbert S M & Lian T M (1998) Induced and spontaneous Ig E antibodies to Dermatophagoides farinae in dogs and cats - evidence of functional heterogeneity of IgE. Vet Derm (3), 179-184 Wiley Online Library.
  • Hämmerling R & de Weck A L (1998) Comparison of 2 diagnostic tests for canine atopy using monoclonal anti IgE antibodies. Vet Derm (3), 191-199 VetMedResource.
  • Olivry T, Guaguere E & Heriret D (1997) Treatment of atopic dermatitis with misoprostal, a prostaglandin E-1 analogue - an open study. J Dermatol Treat 8 (4), 243-247 ResearchGate.
  • Schwartzman R M & Mathis L (1997) Immunotherapy for canine atopic dermatitis - efficacy in 125 atopic dogs with vaccine formulation based on ELISA allergy testing. J Vet Allergy Clin Immunol 5 (4), 144-152 VetMedResource.
  • Codner E C & Griffin C E (1996) Serologic allergy testing in dogs. Comp Cont Ed Prac Vet 18 (3), 237-248 VetMedResource.
  • Olivry T, Moore P F, Affolter V K & Naydan D K (1996) Langerhans cell hyperplasia and IgE expression in canine atopic dermatitis. Arch Dermatol Res 288 (10), 579-585 PubMed.
  • Ritschel W A (1996) Microemulsion technology in the reformulation of cyclosporine - the reason behind the pharmacokinetic properties of Neoral. Clin Transplant 10 (4), 364-373 PubMed.
  • Paterson S (1995) Additive benefits of EFAs in dogs with atopic dermatitis after partial response to antihistamine therapy. JSAP 36 (9), 389-394 PubMed.
  • Willemse T (1985) BSAVA Education Committee commissioned article. Atopic skin disease: a review and a reconsideration of diagnostic criteria. JSAP 27 (11), 771-778 VetMedResource.

Other sources of information

  • Bevier D E (1990) Long-term management of atopic disease in the dog. Vet Clin North Am 20, 1487-1507.

Other Sources of Information