Were you able to see the spider responsible for these bites? Are there other signs or symptoms present? Unless a spider is observed in the act of biting, it should not be assumed that a spider bite has occurred. If bitten by a spider, however, you should clean the site of the spider bite well with soap and water. Apply a cool compress over the spider bite location and aspirin or acetaminophen may be used to relieve minor signs and symptoms in adults. Most spider bites are harmless, and will require no first aid.
The causes of a rash are extremely broad, which may make the evaluation of a rash extremely difficult. Try not to scratch. If you do, the rash may take longer to heal and you'll be more likely to develop an infection or scar. Antihistamines or hydrocortisone cream could help but it would be best to see your doctor for proper evaluation through thorough history and complete physical examination, and management. This link may be helpful: http://en.wikipedia.org/wiki/RashTake care and keep us posted.
These could be due to bed-bugs or some other insects which have elicited the allergic reaction.
Allergies are your body's way of reacting to perceived threats in your environment. When the body is exposed to a substance you are allergic to, called a trigger or allergen, your immune system tries to fight off the assault by producing an antibody called immunoglobulin E (IgE). The problem is, these antibodies cause your cells to release proteins called histamines, which in turn can cause itching, swelling, bumps etc.
Insect bites are common triggers of an allergy rash apart from certain foods and medications etc.
Treatment of allergies is with anti-histamines like Cetrizine. Anti-itch lotions can be used on the bumps.
In the case of bedbugs, antihistamines have been found to reduce itching in some cases, but they do not affect the appearance and duration of the lesions. Topical corticosteroids, such as hydrocortisone, have been reported to expediently resolve the lesions and decrease the associated itching.