When a part of the skin develops in an abnormal growth or is different comparing to the skin surrounding it, it is known as a skin lesion. There are primary and secondary skin lesions.
Primary skin lesions are generally seen from birth and a birthmark is an example of one. These lesions are usually present due to changes in colour; others can develop over time like an age spot. Others lesions that develop or occur over one’s lifetime and are known as blisters, macules, nodules, papules, pustules, rash, wheals, crusts, ulcers, scales, scars, skin atrophy etc. Certain bacteria or viruses can also compromise the skin barrier and result in lesions.
Secondary lesions usually result due to the progression of primary lesions. The original lesion changes due to natural evolution or external factors like scratching that can aggravate existing lesions.