Health
A round bald patch on the muzzle, then one on a leg, then a red ring on your child's arm. Ringworm is treatable, but with tests and patience, not any old cream.
Caution. Bald patches spreading fast, pus or thick crusts, a very young puppy, or people at home with weakened immunity: book a visit with your own vet within the next few days. Until then, the dog does not sleep with the children.
Do not look for the answer in a Facebook group, on TikTok or on a forum. Look for someone trained for this: your dog's own veterinarian, the only person who can examine, investigate and treat them.
Use this page to know what to observe, what to note and what to ask at the appointment, not to treat at home. If you still have doubts after a consultation, ask another vet or a specialist (dermatologist, internist) for a second opinion, not a group. And if you do not have a regular vet yet, find one now, while your dog is healthy: how to choose a veterinary clinic.
You are stroking his muzzle and your thumb slides over a smooth spot. A closer look shows a round bald patch about the size of a large button, its edge slightly flaky, as if someone had sprinkled dandruff on it. He isn't scratching. A week later there is another one on a front leg, and your child, who sleeps with the dog, shows you a red ring on their forearm that itches a bit. That is the classic start of ringworm, or dermatophytosis. It is treatable, but treatment runs for months, it spreads to people and other animals, and it needs proper tests. A cream grabbed off the chemist's shelf won't sort it.
Ringworm isn't a midnight dash to the emergency clinic the way a poisoning is. A few situations still deserve a call to your own vet on the day you notice them:
When you ring, describe the patches and ask how they want you to arrive. Some practices would rather you go straight into a consulting room than sit with an infectious dog among other animals in the waiting area.
In everyday speech "fungus" covers two conditions with very little in common. Worth separating them straight away, because one spreads to people and the other doesn't.
Ringworm is the subject of this page. The fungi behind it live in the hair shaft and in the outermost layer of skin. Dogs pick them up from an infected animal (very often a cat), from soil if they dig, or from rodents if they hunt mice or poke about in burrows. The spores survive in the environment for a long time, up to around eighteen months, on brushes, blankets and furniture.
Malassezia is a yeast that lives on every healthy dog's skin. It only multiplies when the skin is already unwell, most often because of an allergy. Then you see greasy red skin, notice a rancid smell, the paws turn brown from licking and the ears get grubby quickly. The itch is intense. You can't catch it from the dog, and it is treated alongside whatever caused it.
Before the appointment, gather information. Your vet makes the diagnosis, but you are the one who has watched the patches change.
Photos. Photograph each patch with a ruler or a lighter beside it for scale, in the same light, every two or three days. Ringworm usually gives round or irregular bald patches with broken hairs at the edge, dandruff-like scale or small crusts. The skin may be its normal colour or slightly pink. The textbook ring, red at the edge and clear in the middle, is more common in people than in dogs.
Where. Muzzle, around the eyes, ears, paws and front legs. Those are the parts that touch the ground and other animals, so that is where patches tend to show up first.
Itch. Plenty of dogs with ringworm barely scratch at all. If yours is scratching himself raw, your vet will think of allergy, parasites or Malassezia first.
Contacts. A new cat in the house or garden, a recently arrived puppy, digging in the garden, mousing, a stay in kennels or a trip to the groomer. Then any other pets with patches, and any people at home with red marks on their skin.
| Cause | What you see | Spreads to people? |
|---|---|---|
| Ringworm | Round bald patches, broken hairs, scale, little itch | Yes |
| Malassezia | Greasy red skin, rancid smell, brown paws, intense itch | No |
| Demodicosis (a mite) | Bald patches around the eyes and muzzle, mostly in puppies | No |
| Sarcoptic mange | Very intense itch, ear edges and elbows | Yes, briefly |
| Bacterial infection of the hair follicles | Spots, crusty rings, often on the belly | No |
| Hot spot | Moist, red, painful area that appears within hours | No |
In a photo, half of those rows look much the same. That is why your vet won't diagnose from a glance.
There are clear international guidelines for ringworm, and most practices follow them. Expect something like this:
Ask about the cat as well. Cats can carry the fungus without a single patch, and then the dog keeps catching it back from them however carefully you treat him.
Spores are tiny and cling to dust, and disinfectant on its own doesn't reach them. You get them out by scrubbing and hoovering, again and again. Hoover twice a week and empty the bag or canister outside. Wash surfaces with detergent first, then go over them with the disinfectant your vet recommends. Blankets and beds go in the machine at the highest temperature the fabric will take, twice. Clean brushes and combs thoroughly or replace them. If you can, give the dog a room with a washable floor and no rugs during treatment; it is far easier to keep clean.
It is two months of work, maybe more. Ringworm treated all the way to the end stays finished. Half-treated, it can bounce between dog, cat and children for years.
What dog owners search for most often on the internet about this problem, with the short answer. The answers are a guide only: the decision belongs to your dog's own vet, after an examination.
Round or irregular bald patches with broken hairs at the edge, dandruff-like scale or small crusts, mostly on the muzzle, around the eyes, on the ears and paws. Many dogs don't scratch at all, and the neat red ring you know from people is rare. Other skin conditions look much the same, so your vet makes the diagnosis with tests.
Yes. You catch it from direct contact with the dog or from hair and spores left around the house. In people it shows as an itchy red ring, often on the arms, neck or face. Children and anyone with weakened immunity are most at risk. Washing your hands, keeping the dog out of the bed during treatment and cleaning the house cut the risk a great deal.
Several weeks, often two to three months. You stop when the check-up cultures come back negative, often twice in a row; hair growing back isn't enough. Stop too early and the patch returns. In a healthy dog the infection can clear on its own over a few months, but all that time he is shedding spores round the house.
Ringworm is a contagious fungus of the hair that gives round bald patches and little itch. Malassezia is a yeast that normally lives on the skin and multiplies once the skin is already unwell, often because of allergy: greasy red skin, a rancid smell, brown paws and an intense itch. Malassezia doesn't spread to people and is treated along with its cause.
Scrub and hoover, repeatedly. Hoover twice a week and empty the bag outside, wash surfaces with detergent and then the disinfectant your vet recommends, and wash blankets and beds at a high temperature, twice. Clean or replace brushes. Spores can survive indoors for over a year, so a gap in the cleaning usually brings the infection back.
The information on this page is educational and does not replace an examination. For full details and a diagnosis, consult your dog's own veterinarian.
They often come together: the same causes, plans that complement each other.
Claws on the belly at midnight, paws licked red, an ear infection every summer. Behind the word "allergy" sit at least three diseases, each with its own plan.
Tufts on the sofa are one thing. Round patches, bald flanks or a dog scratching himself raw are something else. Here is how to tell them apart.
Crusted ear edges, bare elbows, nights of scratching. Or round bald patches round the eyes of a puppy who never scratches. One name, two diseases.
Nothing in the morning, a red wet patch under the ear by evening, the size of your palm next day. Hot spots spread fast and nearly always have another cause.
We work with your dog's behaviour, not its health. For any sign described here, book an appointment with your own vet; the related services page explains how to choose a clinic.