Clinical features:
(1) It involves sun-exposed skin, typically on the face (rarely on the hands and forearms).
(2) It may be exacerbated by sunlight and UV-A or UV-B lights, so tends to be seen during the summer months.
(3) It is more often in women than men. In women it is more common during child-bearing years.
(4) It is more common in Hispanics and Asians.
Facial patterns:
(1) centrofacial (cheeks, forehead, upper lip, nose and chin)
(2) malar (cheeks and nose)
(3) mandibular pattern (ramus of the mandible)
Precipitating factors:
(1) in women, pregnancy or use of oral contraceptive agents
(2) drug-associated (phenytoin or methylphenytoin)
(3) endocrine dysfunction
(4) liver dysfunction
(5) nutritional deficiencies
(6) idiopathic
The differential diagnosis includes:
(1) post-inflammatory hyperpigmentation.
(2) SLE (if a malar pattern)
Therapy:
(1) sunblocking creams
(2) bleach
(3) time
(4) if possible, change in precipitating cause (stopping medications; treating underlying disease; it may reverse after delivery if associated with pregnancy)
