It really depends on what is causing the itchy patches. Have your dog checked by a vet first to make sure it isn't something serious. If these are hotspots (caused by the dog constantly licking or chewing at a spot) an easy remedy is to bathe the area with goldenseal (an herbal antiseptic). Open a goldenseal capsule and dissolve the contents in hot water - it won't all dissolve. Wait for the mixture to cool and apply to hot spots with a gauze pad or cotton ball.
Another remedy is to open a capsule of Vitamin E and put on the hotspot. If the itchiness is from Allergies, you can use stinging nettles - one capsule for every 50 lbs of body weight 2 or 3 times a day.
Make sure you check with your vet before using any of these remedies.
Many dogs have bald patches under their arms. It is completely normal. Many dogs will also have bald patches on their elbows, the joint on the upper front leg.
Sun damage
The word patches is a noun, a plural noun; and a verb, a form of the verb to patch. Examples:As a noun: He had bald patches in his hair.As a verb: He patches up his relationship with his wife after every argument.
This sort of problem requires the urgent attention of a doctor don't waste any time.
http://www.boxerforums.com/losing-patches-of-fur-t19467.html
A guinea pig's color has nothing to do with its life, except for if it is getting bald patches or patches of color that weren't there before.
Alopecia areata.
when your guinea pig has a sign of thinning fur or bald patches or a wet nostrils.
a fungal skin infection
It is used on scalp. You should apply it in the centre of the bald area. And your hair should be dry and clean. The treatment is used twice daily, and it works very well.
Some people go bald for genetic reasons and it is not possible to prevent this. Some men do try hair transplants to cover the bald patches but these are not always successful and do cost a lot.
Going bald (losing the hair on your head) can be the result of a medical condition or treatment but it can also be a natural part of aging (especially in men).