Triads in dermatology.

It is imperative for any dermatology resident to have a good knowledge of the various triads in dermatology. For an easy grasp over this topic, we have grouped the various triads on the basis of their etiologies.

A non healing ulcer on scalp.

Angiosarcoma is a soft tissue tumour with a dismal prognosis. We present a 74 year old male presenting with a non healing ulcer on the scalp. On histopathology a diagnosis of angiosarcoma was made.

Diagnostic utility of dermatoscopy in hydroquinone-induced exogenous ochronosis.

Background:   Hydroquinone is the preferred topical bleaching agent used in the treatment of melasma. The adverse effects of its chronic use are confetti-like depigmentation and exogenous ochronosis. Exogenous ochronosis manifests clinically with gray-brown or blue-black hyperpigmentation, as well as pinpoint hyperchromic caviar-like papules over the malar region.

Trigeminal trophic syndrome: a rare entity.

Trigeminal trophic syndrome is a rare condition resulting from self-manipulation of the skin after a peripheral or central injury to the trigeminal system. The syndrome consists of a classic triad of anaesthesia, paraesthesia, and a secondary persistent or recurrent facial ulceration. We describe a 60 year-old woman who developed this syndrome as a sequel to the gasserian ganglion block for trigeminal neuralgia.