White flakes on red bumps may be caused by seborrheic dermatitis, psoriasis and atopic dermatitis. 1. Seborrheic dermatitis: the clinical manifestation of this disease is an erythematous rash, often with greasy scales on the surface, mostly grayish-white. The cause of the disease may be related to age, heredity and disease. 2. Psoriasis: the typical clinical manifestations of this disease are erythematous spots, papules or plaques covered with silver-white scales, limited or widely distributed. The disease is an immune-mediated, chronic, recurrent, inflammatory, systemic disease induced by both genetic and environmental factors. 3. Atopic dermatitis: The disease is characterized by dry skin, chronic eczema-like dermatitis and intense itching, and patients may also have erythema, papules and scales. The cause of the disease may be related to genetic, environmental, and immune abnormalities. There is no single disease that causes white flakes on red bumps, and patients are advised to seek medical examination to clarify the cause.