What could be causing something resembling goosebumps on the outer side of the arm?

Keratosis pilaris-like papules appearing on the outer side of the arms may be caused by various skin conditions. 1. Keratosis Pilaris: This is a skin condition associated with genetic factors, vitamin deficiencies, and metabolic disorders. It is characterized by localized hyperkeratosis and clogged hair follicles, leading to perifollicular papules resembling goosebumps. 2. Eczema: A skin inflammation triggered by various internal and external factors such as temperature changes and allergens. It presents with papules and other skin lesions, often accompanied by local erythema and itching. 3. Urticaria: An allergic reaction induced by factors such as food, medications, or infections. It manifests as wheals of varying sizes and rash resembling goosebumps on the outer arms, commonly associated with itching. In addition to the above causes, other skin diseases or environmental factors may also contribute to such skin issues. It is recommended to seek timely medical attention for an accurate diagnosis by a qualified physician, so that the specific cause can be identified and appropriate treatment initiated.