Freckles are macular lesions produced by UV radiation induced temporary excess production of melanin by a normal number of activated melanocytes in a genetically predisposed individual. They usually first appear in a fair complexioned child around the age of 3–5 years as multiple, symmetrical, small, discrete, brown macules on the face, shoulder and back. Characteristic features are seasonal variation and immediate pigment darkening. Freckles increase in number, size, and pigmentation during the summer and become scanty, smaller, and lighter in winter.
Lentigo is a benign, circumscribed, small, brown, nearly macular cutaneous lesion that results from an increase in the number of melanocytes. These are a more permanent macule of pigmentation similar to freckles but they tend to persist in the winter. Solar lentigos (also called 'liver spots') occur in older people on exposed skin because of actinic damage.
Melasma is an acquired, circumscribed, pigmentary disorder characterized by more or less symmetrically distributed, medium to dark brown macules with defined geographic borders, affecting the sun exposed areas, particularly the forehead, cheeks, temples and upper lip. It is a common skin condition among darker individuals including Indians. It is relatively more frequently encountered among females. They can occur spontaneously but may also be associated with sunlight exposure, oral contraceptives, pregnancy and endocrine dysfunction, ingredients in cosmetics, some drugs (like phenytoin). Melasma may also be familial.
Idiopathic guttate hypomelanosis
This condition is very common among the elderly of both sexes. Rarely, it can be encountered in children. It is of unknown etiology. It presents with small (2-4 mm) asymptomatic porcelain-white macules, often on skin exposed to sunlight. The borders are often sharply defined and angular.
This is one of the most common causes of pale skin. It is much more common in people with pigmented skin. It is seen as a consequence of eczema, acne or psoriasis. Providing the skin disease is controlled, the pigmentation will recover slowly after many months.