Hair loss is often result of skin allergies and excessive licking and chewing.
If there are no sign of skin irritation, this is a sign of inadequate protein intake. Other deficiencies, particularly of trace minerals, will slow hair growth.

There are 2 remedies that are especially useful for simple hair loss unaccompanied by other symptoms.
Homeopathic
Selenium 30C: If this treatment is successful, you will see signs of hair growth within a month. Do not repeat this remedy without any supervision. Use the feeding method below.
Sepia (Ink from cuttlefish.) 30C. This remedy suit female that loose hair after giving birth and nursing the young. Not necessarily a nutritional problem; is more likely a hormonal imbalance, which can be corrected in this remedy. Use the feeding method below.
This method you give only one treatment. Give two whole pellets or 3 pellets crushed into powder. Place on the tongue. Give no food and water before and after treatment. Wait for a full month before any further treatment; it will be a mistake to repeat the remedy in a few days. If by the end of the month no improvement is evident, you will need to choose a new medicine.
Symptoms Of Skin Disorder are:
1) Very Dry Skin
2) Flakiness or white scales resembling dandruff
3) Large brown flakes
4) Redness and irritation
5) Itching (ranging from slight to so severe that blood is drawn)
6) Greasy hair and foul odor to the skin and its secretions
7) Pimples and blisters that form between the toes and discharge blood and pus
8) Brown, black or gray skin discoloration
9) Formation of scabs or crusts, and hair loss.
10) Chronic inflammation inside the ear canal
11) Anal gland problem
12) Underactive (hypoactive) thyroid glands as related to skin disease.
What Are The Causes Of This Overall Disorder?
1) Toxicity - Probably most of it from poor quality food and some of it from other sources, like environmental pollutants and deliberately applied pest control chemical.
2) Vaccinations - Inducing immune disorders in susceptible animals
3) Suppressed disease - remains of an inadequately treated condition that never was cured and that may periodically discharge through skin.
4) Psychological Factors - boredom, frustration, anger, and irritability. However these are secondary issues that simply aggravate an already-exiting problem.
Homeopathic
Rhus Toxicodendron (poison ivy, poison oak) 6C: Suitable as a temporary medicine when itching flares up and is very intense. There tends to be swelling of the skin and relief from applying warm compresses.
USE METHOD 2
Graphites (a form of carbon) 6C: This remedy is indicated when the "hot spot" ooze a sticky, thick discharge, about the consistency of honey.
USE METHOD 2
Mercurius vivus (0r solubilis) (mercury, quicksilver) 6C: Use this one if there is a pus-like yellowish or greenish discharge. Also the hair will tend to fall out eruptions, leaving raw, bleeding areas. The condition is usually worse in hot weather or in very warm living quarters. Frequently these animals will have red gums, problems woth the teeth and very bad smelling breath.
USE METHOD 2
Aresenicum album 6C: This remedy suit dogs with skin eruptions that cause a great deal of restlessness and discomfort. They seem to be driven almost insane - constantly chewing. licking and scratching. The skin lesions are very red and dry with loss of hair and an "eating away" of the skin, leaving angry red sores. Especially indicated if the dog becomes very thirsty and chilly as well.
For animals with a long term, low grade condition of itchy, greasy, or dry ans scaly skin (who may also have an underactive thyroid), start by fasting one time every week. Offering only broth. The rest of the time feed only natural food and supplements. It is important that you don't feed commercial food or supplement with questionable ingredient, because part of your pet's problem may be a hypersensitivity or allergy to artificial additives or processed ingredients. If skin is greasy and foul-smelling bath your dog at least once per week. If skin is dry, bath less often.
USE METHOD 2
Sulphur (the element) 6C: This remedy is very helpful for dry, itchy skin, especially your dog tend to be thin, "lazy", and not very clean, with red looking eyes, nose or lips. These animals generally don't like a lot of heat, but sometimes will seek out a warm stove in cooler weather.
USE METHOD 6a
Graphites (a form of carbon) 6C: These dogs tend to be overweight, constipated, and easily overheated. Eruption ooze sticky fluid. The skin is easily inflamed, even by slight injuries like scratches, and it does not heal easily. The ears can be plagued with irritationm a bad smell abd waxy discharge.
USE METHOD 6a
Thuya (or Thuja) occidentalis (arborvitae) 30C: This remedy is an antidote to illness following vaccinations. Many of the animals developed skin problem within a few weeks after vaccinated. This remedy occasionally during treatment really helps such dogs recover. Another time to consider Thuya (or Thuja) is when other medicines have not done much good. If so, giving Thuya and then going back to one of the above remedies will sometimes result in progress.
USE METHOD 4
Silicea (silicon dioxide, quartz) 30C: If the problem persist in spite of the advice given so far, especially if there is an excessive appetite, stealing food, scavenging - even leading to overweight - then this medicine will be of use. Do not repeat this medicine.
Note: In general, these deeply, ingrained skin conditions require patience and persistence. You will usually see clear, beneficial effect from the program within 6-8 weeks.
Because vaccines tend to aggravate the condition, it is very important to avoid them during the treatment period. Sometime medicines like those used for heartworm prevention will set offf an attack. In this case it is best to use the monthly type of heartworm medication and give it only every 6 weeks (or stop using it altogether in severe cases).
Some cases will not completely recover no matter how long you treat them (though they generally improve). These need more individualized treatment with other homeopathic remedies or one of the holistic approaches.
For the animal to suffer hair loss, try a slightly different program. Sometimes a pet will just begin to lose hair without any other apparent problem. Or the loss could be the result of poisoning - not necessarily the intentional kind, but rather the accumulation of toxic substance that may affect sensitive individuals. Common agents to consider include fluoride ( in some drinking water and commercial pet food) and aluminum (from use of aluminum bowls or cooking utensils). Sensitivity to aluminum seems to vary and not all animals show these reaction. Those that are poisoned by aluminum tend to have constipation as well.
It is also possible for hair loss to reflect a disturbance in the endocrine glands (especially hypothyroidism) or a deficiency of a certain nutrient. If your veterinarian has diagnosed either of these problems, then feed only the natural diet with added kelp powder. This particularly important, because the powder's iodine content will help to stimulate the thyroid. Give 1/2 to 2 teaspoon of kelp powder daily (amount depend on your dog's size). In addition, give 250 to 1,000 mg of vitamin C 2 time a day to aid detoxification and 5 - 20 mg of chelated zinc once a day to enhance the elimination of heavy metals. Discontinue of using aluminum utensils and fluoridated water.
USE METHOD 4
Thuya (or Thuja) occidentalis (arborvitae) 30C: Try Thuya first because it is an antidote to the effects of vaccination, which is the primary reason for a persistently poor hair coat for poor hair growth. (Sometimes hair loss is at a normal rate, but the issue is that no new hair grows in to replace it; in such case this remedy suit it well)
Selenium (the element) 30C: Indicated for excessive hair loss with no new growth, especially if there are no other symptoms of illness. Use it after trying the Thuya (or Thuja) occidentalis (arborvitae) 30C, if the remedy is not sufficient to resolve the problem.
Sepia (cuttlefish ink) 30C: If an animal develops the hair loss after giving birth use this remedy. Give one dose.
Method 2
Give 1 or 2 pellets every 4 hours for a total of 3 treatments. Provide no food for ten minutes before and after treatment. No further homeopathic treatment will be use for the next 24 hours. If your dog is not noticeably improve by then, try another remedy or go to one of the other treatment choices.
Method 6a
Here you will repeat the does over a longer period. You will give it once every day. Provide no food for 5 minutes before and after giving the medicine.
The treatment usually take 7 - 10 days. If it has helped some but not enough, this can be an indication that either a better medicine should be used or there is something else slowing down the recovery. It is best to get advice from a holistic veterinarian at this point.
Method 4
This method you give only one treatment. Give two whole pellets or 3 pellets crushed into powder. Place on the tongue. Give no food and water before and after treatment. Wait for a full month before any further treatment; it will be a mistake to repeat the remedy in a few days. If by the end of the month no improvement is evident, you will need to choose a new medicine.
Herbal
Garlic (allium sativum): Give daily 1/4 to 1 whole clove (fresh grated or minced) or 1 to 3 small garlic capsules. You can continue giving garlic indefinitely, as it also dicourages fleas.