What are the causes of skin rash and pimples in anal area?

Condition analysis:
Hi. As per your complains it seems you have boils or furuncle on peri-anal region.
Donot use hydrocortisone cream, it is mild steroid and will not cure your condition and there will be recureence.
U can use Fusidic acid cream (fusiderm)- a good antibiotic cream twice daily on affected part for 7-10 days. It condition doesnot subside than u can consult a dermatologist as it may need oral antibiotics and analgesics

Instructions:
1. Fruit Peels:
Peels of a few fruits are very effective on skin allergies. Rub banana peel or watermelon rinds on the infected area, to liberate you from that itch and irritation associated with most types of allergies.

2. Honey:
Bees produce honey and we use to relieve allergies! In order to gradually become inoculated against the irritating effects of pollen, you need to consume this golden syrup daily.
 
3. Steam:
Pour some boiling water into a bowl, drape a towel over your head, and inhale deeply through your nose for 5 to 10 minutes. (Do not get your face too close to the water, as you may scald yourself.) You can also add some green tea or peppermint tea leaves to the water. If you are really clogged up, this well may be the thing you need.

4. Eucalyptus Oil:
The strong aroma of eucalyptus oil helps to open your sinuses and nasal passages. Add a few drops of this therapeutic oil to a bowl of steaming water, or on the floor of the shower, just before you step in. Remember, do not swallow the oil or apply it directly on your skin as it can be toxic in concentrated amounts.