Leprosy (Hansen's Disease)

Skin Lesion: Hypopigmented or erythematous (reddish) patches. These may be solitary or multiple, often with a loss of hair or sweating within the patch.

The diagnosis of leprosy is done clinically. Laboratory-based services may be required in cases that are difficult to diagnose. Leprosy is diagnosed by finding at least one of the following cardinal signs (WHO):

• Definite loss of sensation in a pale (hypopigmented) or reddish skin patch.
• Thickened or enlarged peripheral nerve, with loss of sensation and/or weakness of the muscles supplied by that nerve.
• Positive Slit Skin Smear (SSS).

Pityriasis Versicolor (Panau)

• The Clue: Multiple small, scaly macules on the upper trunk. Positive Besnier’s Sign (scaling when scratched).
• Vs Leprosy: Versicolor has completely normal sensation and is often itchy. Leprosy patches are anesthetic (numb).

Tinea Corporis (Ringworm)

• The Clue: Annular (ring) shape with central clearing and an active, itchy, scaly border.
• Vs Leprosy: Sensation is preserved in Tinea. Leprosy patches are usually dry and non-itchy.

⚠️ Clinical Pearl: If the patient cannot feel a wisp of cotton wool in the center of a pale patch but can feel it on normal skin, Leprosy is the top differential.

⚠️ Notify.

⚠️ If SSS test is negative but you still suspect leprosy, refer dermatology for skin biopsy.

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