There is a patch of small rice-sized bumps on the arm, consider the following possibilities: The first possibility is perihistiasis, which is mainly due to a genetic disorder that results in follicular consistency papules on the extensor side of the upper arm, often accompanied by drier skin, which can be treated with topical vitamin A acid ointment once a day at night or tazarotene gel application. If the condition is accompanied by itching and dryness, it can be treated with topical hydrocortisone butyrate ointment 1:1 mixed with zinc oxide borate ointment. In the second case, eczema may be more likely to be caused by allergy to sunlight or contact with chemical fiber clothing. In addition to the small bumps and itching sensation, you can take oral Orotadine Hydrochloride tablets and apply topical Mometasone Furoate ointment for treatment.