Causes of a Red Rash on My Arm

Causes of a Red Rash on My Arm<br /><br />Strong chemicals may cause an irritating, nonallergic reaction in the skin, leading to the formation of a red rash at the site of contact. The skin typically swells and appears waxy. This condition, known as irritant contact dermatitis, reflects physical damage to the skin, explains the New Zealand Dermatological Society on the health information website DermNet NZ. Examples of chemicals that may splash on the arms and cause irritant contact dermatitis include strong detergents, paint thinner and other solvents, drain cleaner and certain glues. is a form of eczema characterized by irritation of the nerve endings associated with the itch sensation. An intensely itchy area of skin may develop at the site of an insect bite, scar or contact dermatitis. As the patient scratches the involved area, it becomes itchier, explains the University of Michigan Health System. The itch scratch itch cycle continues, causing a thickened, inflamed red patch that may become infected. The infection often begins with a small cut, insect bite or scratch. Bacteria invade the skin through the wound and rapidly spread outward from the site of entry. The affected area becomes red, swollen, painful and warm to the touch. Expansion of the skin redness signals spread of the infection. The species of bacteria most frequently associated with cellulitis include Staphylococcus aureus, group A streptococci, Haemophilus influenzae, Pseudomonas aeruginosa and group B streptococci, reports The Merck Manual for Healthcare Professionals.