The problem could be internal, where something is affecting the growth of your dog's hair follicles. It could also be external - an infestation of parasites can lead to infections that cause hair loss.
Alopecia: the external causes
Of all the nasty little creatures that can live on your dog, look out for the Demodex mite. It's most likely your dog will be carrying a few of these, but too many can cause mange, which is an inflammatory disease of the skin. The symptoms include excessive scratching, red skin, and hair loss. If the infection remains concentrated in one area then it will usually clear up on its own - this happens in approximately 90% of mange cases. However, if it spreads onto other places of the body then take your dog to a vet; it's likely they'll need a course of medication to clear up the problem.
Just like their owners, dogs can develop allergic reactions to pretty much anything. Allergic reactions cause itchy skin, excessive scratching, and in some cases even hair loss. Anti-histamines are a short-term solution, but you don’t want your dog on medication forever. This means you'll need to find the source of the problem. You can try identifying the culprit through trial and error, removing certain items from your home until the dog gets better. But anything could be causing the bad reaction so its likely to be a very lengthy process. Take them to a local vet instead. They can run a series of designed tests to identify the most common allergies.
As with many medical issues, diet can play a big part. The high number of colourants and preservatives in dog food have been linked to the increasing number of allergies and nutritional deficiencies, both of which can cause alopecia. Focus on a high-quality organic diet with lots of fresh food and nutrients. Ask your vet for advice.
Alopecia might be a symptom of an underlying health issue
If it doesn't appear to be any external factors causing the alopecia, then it might be a symptom from something else. This could be one of many things, but here are a few of the more common causes:
Hyperthyroidism and Canine Cushing's disease are caused by hormonal imbalances, and both can cause hair loss. Again, the alopecia will be a symptom rather than a cause, so its well worth getting your dog checked by a local vet. Fortunately, endocrine disorders can be treated and managed with medication, but an early diagnosis will certainly make things easier for you and your dog.
Unfortunately, hair loss might be genetic. As some men are more prone to losing their hair early, so are certain breeds of dog. Dachshunds are particularly susceptible to alopecia and as of yet, there is no cure for baldness in dogs or men. Focus on managing the condition instead; moisturisers and ointments will stop your dog's skin getting too dry, and make sure you limit their exposure to direct sunlight.
Dogs are quite sensitive creatures. Stress or anxiety could be causing their hair loss. Dogs get stressed for many different reasons. It could be a change in their environment, a lack of exercise or stimulation, or a reaction to a traumatic incident. Luckily its quite easy to spot. Aside from any potential hair loss, you’ll definitely notice a change in your dog's behaviour. They may seem less energetic. They may not want to eat their food. They may not seem like their ‘normal’ self. Focus on finding the root cause. Once that’s been managed properly, your dog will soon get back to their old self. Their hair will also grow back.
Bitches lose the hair around their stomach as they approach the last few weeks of pregnancy. This makes feeding the puppies easier, and it's nothing to worry about; the hair will grow back in its own time.
Fungal or bacterial infections
Certain fungal and bacterial infections can lead to alopecia. Bacterial folliculitis is the most common cause of hair loss in dogs. It creates distinct circular bald patches surrounded by redness and scabbing. It's treatable, but your dog will need to see a vet. It's also important for your own health; certain fungal and bacterial infections are zoonotic, which means that you can catch them too.
In itself, alopecia is not a particularly serious issue. For some dogs, it's a natural part of the ageing process, and there isn't much we can do about it. However, alopecia is usually a sign of underlying health issues so any hair loss in younger dogs needs to be checked by a vet. But don't worry, most of these conditions are treatable. In the meantime, focus on keeping your dog's skin and coat healthy with a high-quality organic and regular grooming sessions.