Introduction
Dogs can suffer from a variety of skin conditions that cause itching, hair loss, sores, and irritation. One common canine skin disorder is dermatitis, which refers to inflammation of the skin. Dog owners may wonder if dermatitis is contagious to humans. This article will examine if and how humans can develop dermatitis from dogs. We will cover the differences between human and dog skin, look at diseases dogs can transmit, discuss allergic reactions, precautions, diagnosis, and treatment. The goal is to provide dog owners with a thorough understanding of the risks, symptoms, and management of human dermatitis contracted from dogs.
What is Dog Dermatitis?
Dog dermatitis is an inflammatory condition of the skin in dogs. It is one of the most common health problems in canines. Dermatitis causes the skin to become itchy, red, and irritated.
There are many potential causes and types of dermatitis in dogs, including:
- Allergic dermatitis – triggered by allergies to food, flea bites, pollen, or other substances. This leads to itchy skin reactions.
- Contact dermatitis – caused by contact with irritating substances like plants, chemicals, wool, or synthetic fibers. It results in a rash or blisters on the skin.
- Flea allergy dermatitis – caused by flea bites leading to severe itching, redness, hair loss, and skin infections.
- Bacterial dermatitis – bacterial skin infections often secondary to allergies, seborrhea, or parasites.
- Yeast dermatitis – overgrowth of yeast on the skin leading to greasy skin, hair loss, redness, and odor.
- Seborrheic dermatitis – caused by overactive sebaceous glands leading to greasy skin and yellowish crusts.
Dermatitis can be localized to one area of the body or generalized across the skin. It ranges in severity from mild intermittent signs to severe unrelenting lesions and infections.
Key Differences Between Human and Dog Skin
While dogs and humans have the same basic skin structure, there are some key differences between human and canine skin that impact skin health and susceptibility to dermatitis.
Some of the major differences include:
- Thickness – Dog skin is much thinner than human skin. Humans have an epidermis thickness of 0.05-0.1mm while dogs average 0.15-0.3mm.
- Hair Follicles – Dogs have many more hair follicles concentrated in one area than humans. They have up to 1,000 follicles per square centimeter compared to humans who average 100 follicles per square centimeter.
- Sweat Glands – Humans have extensive sweat glands spread over our entire body to help regulate temperature. Dogs only have sweat glands on their paws and nose.
- Fatty Layer – Humans have an extensive subcutaneous fat layer under our skin for insulation and padding. Dogs have minimal fat deposits under their skin.
- Skin pH – Human skin pH averages 5 while dog skin pH is more neutral at 7.
- Skin Immunity – Dog skin has a weaker innate immune function compared to human skin.
These differences mean dogs are more prone to skin diseases like dermatitis. Their thinner skin layer, concentration of hair follicles, and reduced immune function make dogs more vulnerable to skin inflammation and infections.
Can Humans Get Mites that Cause Mange in Dogs?
Mange in dogs is typically caused by microscopic mites that burrow into the skin and cause irritation and itching. There are a few different species of mites that affect dogs, including sarcoptic mange mites (Sarcoptes scabiei), demodectic mange mites (Demodex canis), and cheyletiella mites (Cheyletiella yasguri). These mites are species-specific, meaning they typically only infest dogs and not humans.
However, humans can get infested with a different mite species that causes a similar condition called scabies. The scabies mite that affects humans is called Sarcoptes scabiei var. hominis. This is closely related to the sarcoptic manage mite in dogs, but is genetically distinct and does not generally cross between species. So dogs cannot give human scabies to owners, and human scabies mites do not cause mange in dogs.
The bottom line is that the mites that cause mange in dogs are not the same as those that cause scabies in humans. While mites can jump between some animal hosts, the mites stay species-specific between dogs and humans. So humans do not need to worry about catching mange from a dog. Proper hygiene and care should be taken around dogs with mange, but the mites cannot live long or reproduce on human skin.
Diseases Dogs Can Transmit to Humans
While dogs and humans have different skin biology, dogs can transmit some skin diseases and infections to human owners through direct contact. Some of the main zoonotic (animal-to-human) skin diseases that dogs can pass to humans include:
Ringworm – Ringworm is a fungal infection that can manifest as ring-shaped rashes on the skin in both humans and dogs. Dogs can transmit ringworm to humans through direct skin contact with the infected area or by spreading fungal spores in the environment.
Leptospirosis – Leptospirosis is a bacterial disease dogs can get through contact with infected urine, water or soil. Some strains can infect humans and may cause a rash in addition to flu-like symptoms.
Scabies – Scabies mites can jump from dogs to humans in rare cases. When transmitted, they burrow into the skin causing intense itching and a pimple-like rash.
MRSA – Some dogs can carry a strain of antibiotic-resistant staph bacteria known as MRSA. This can be transmitted through dog bites or skin contact and cause skin infections in humans.
Tapeworms – Dogs can get tapeworm from ingesting fleas. Tapeworm segments containing eggs can end up on a dog’s skin and contaminate human skin. If accidentally ingested, they can then hatch inside the intestines.
Allergic Reactions to Dogs
While humans cannot catch dermatitis from dogs, they can experience allergy symptoms from exposure to dogs. This is not the same as an infection, but rather an immune system reaction to substances from dogs known as allergens. The most common dog allergens are:
- Dander – Microscopic pieces of skin shed by dogs
- Saliva – Found in dog licks, kisses, toys, bedding
- Urine – Residue found on a dog’s fur
When humans inhale or touch these allergens, their immune system identifies them as foreign invaders and releases chemicals like histamine to attack them. This causes allergy symptoms such as:
- Sneezing
- Itchy, watery eyes
- Runny nose
- Coughing
- Skin rashes
- Hives
The allergy is not contagious and cannot be spread between humans and dogs. But continued exposure can cause chronic allergic reactions. Treatment involves avoiding the allergen source and using antihistamines or allergy shots.
Precautions for Humans Around Dogs with Dermatitis
While the risk of contracting a skin disease from a dog is low, there are some precautions humans can take when interacting with dogs suffering from dermatitis or skin infections:
Handwashing – Thoroughly wash your hands with soap and warm water after touching an affected dog. Avoid touching your face until after washing.
Gloves – Consider wearing disposable gloves when bathing or treating a dog’s irritated skin or lesions. Properly remove gloves after use and discard.
Lesion avoidance – Avoid directly touching open wounds, hot spots, or infected areas on a dog. Do not let them lick or rub their lesions on you.
No kissing – As cute as dog kisses are, avoid mouth contact with a dog that has skin issues.
Monitor your skin – Check your own skin after interactions with an affected dog. See a doctor if you develop any unusual rashes, bumps, or irritation.
Clean bedding – Wash a dog’s bedding, Fabric items can harbor contagious pathogens. Use gloves when handling.
Taking basic hygiene precautions can help protect you from potential skin conditions when caring for a dog with dermatitis. However, the risks are low if you maintain cleanliness.
Diagnosing Dermatitis in Humans
Doctors will diagnose dermatitis in humans through a combination of methods:
Physical Exam: The doctor will visually inspect the affected area, noting any rashes, redness, swelling, blisters, cracking, peeling or scaling of the skin. They will examine the pattern and distribution of the symptoms. Dermatitis tends to cause itchy, red, swollen skin in areas that come into contact with an irritant or allergen.
Medical History: The doctor will ask about potential triggers and timing of symptoms. They will want to know if there’s any family history of skin conditions or allergies. Knowing when the rash started, what exposures preceded it, and what makes it better or worse can help identify the cause.
Allergy Testing: If an allergy is suspected, the doctor may do a skin prick test or blood test to identify specific allergens. Common triggers include pet dander, dust mites, pollen, foods, metals like nickel, and chemicals in products like soaps, detergents and creams.
With dermatitis, there is often a clear relationship between exposure to an allergen or irritant and the onset of an itchy rash. The doctor will work to identify any substances, products, animals or environments provoking symptoms.
Treating Human Dermatitis
If a person develops a rash or dermatitis after contact with a dog, the first step is to identify the underlying cause. Allergic reactions to dogs can sometimes cause dermatitis in humans. For dog-induced allergies, the most effective treatment is allergen avoidance and minimizing contact with dogs. Antihistamines like cetirizine or loratadine may help relieve allergy symptoms.
For dermatitis unrelated to dogs, standard treatments similar to other forms of dermatitis are used. Mild dermatitis can be treated with over-the-counter hydrocortisone cream to reduce inflammation and itching. For more severe cases, prescription topical steroids like betamethasone may be prescribed. Topical calcineurin inhibitors like tacrolimus or pimecrolimus are another option for sensitive skin areas.
Oral medications can also treat widespread dermatitis. Antihistamines help control itching and allergic reactions. Oral steroids may be used short-term for severe flare-ups but carry risks with prolonged use. Immunosuppressants like cyclosporine can calm an overactive immune system. Biologics that target specific parts of the immune response are newer medications used for chronic dermatitis.
In addition to medications, good skin care habits can aid dermatitis recovery. Patients should use gentle, fragrance-free cleansers and moisturizers. Soft, breathable fabrics help prevent skin irritation. Lukewarm baths with colloidal oatmeal can soothe itchy skin. Identifying and avoiding triggers like irritants, allergens or stress is also important.
With proper treatment, most cases of dermatitis can be managed successfully. A dermatologist can help diagnose the type of dermatitis and tailor an effective treatment regimen for an individual patient’s needs.
Conclusion
In summary, dog dermatitis itself is not contagious to humans. Dogs can get various skin conditions, like mange, allergic dermatitis, or bacterial infections, but these cannot be directly transmitted to human skin. Humans and dogs have very different skin types, oil glands, and hair follicles that generally prevent transmission of mites, fungi, or bacteria between species.
However, humans should take some basic precautions around dogs with dermatitis. Allergic reactions can occur, especially among those predisposed to skin sensitivities. Close contact may also result in secondary infections if open wounds or sores are present on the dog’s skin. Additionally, diseases like ringworm are zoonotic and can occasionally spread between dogs and humans. Overall though, dog dermatitis poses a very low risk to human health.
In most cases, dog dermatitis will remain confined to canine species only. But cautious handling of affected animals and proper diagnosis of any skin reactions in humans will help minimize any concerns. While not considered contagious, certain sensible precautions around dogs with irritated skin may be warranted.