Most cases occur between 12 and 30 years of age. Problems with digestion, constipation, or underactive thyroid and anemia seem to be contributing factors. Although germs do not cause them, blackheads can easily become infected. Never use fingers to do it. Then wash with mild soap and water.
Sunlight kills the surface bacteria, and thus clears the condition temporarily.
But sunlight can also stimulate the oil glands, possibly making the condition worse later. Do not overeat. Avoid fat, greasy, or fried foods, ice cream, cream, butter, margarine, chocolate, pastry, sweets, or much starchy food. Eat a nourishing diet of vegetables, but avoid corn. Eat protein foods in moderation.