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Chloasma manifests as pigmented patches on the face which are most often associated with pregnancy, but can appear due to other causes as well not only in the females but in males too. This disease is also known as 'melasma', 'seborrhoeic melanosis' and pigmentation due to pregnancy.
The lesions in chloasma are very characteristic. These are superficial-looking, brownish macules (patches) which are irregular in shape and have a spotty appearance. The margins of the macules are highly crenated but fairly sharp. In size, the macules may be as small as 1 cm, or large enough to cover almost the entire face in the form of a mask. The lesions however, do not occur on any other part of the body, and on the face too, the lesions of chloasma have a very characteristic distribution.
The most common site of involvement is the front of the cheeks on one 01'both the sides. The bridge of the nose is also frequently involved. The lesions may also appear on the forehead in the form of an irregular patch at the centre of the forehead, but sometimes it involves an elongated area just above the eyebrows. When it involves the upper lip, it spares the middle portion of the upper lip which lies just below the nose-this pattern of involvement suggests that the pigmentation is related to exposure to sunlight, because the areas adjacent to the hairline (protected by the scalp hair), the middle part of the upper lip (protected by the nose), the upper and the lower eyelids, and the under-surface of the chin are never involved.
In spite of this distribution, the patient never complains of aggravation due to an excessive exposure to sunlight and the lesions are completely asymptomatic-there is no itching, pain or burning sensation even after prolonged exposure to sunlight. The lesions are completely flat; neither raised above the surface, nor does the skin feel different in these areas. The color is also a peculiar brownish black which can be easily distinguished from pigmentation due to other causes. The extent of involvement varies in different individuals.
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