4 - Dermatology 2025

Comedone

Clinical hallmark of acne

Koebner phenomenon

Traumatized area often develops lesions of psoriasis

Auspitz sign

Removal of scale causes pinpoint bleeding in psoriasis

Filaggrin

Mutation of this protein occurs in atopic dermatitis

Use of emollients especially immediately after bathing

Cornerstone in the management of atopic dermatitis

Medial aspect of the ankle

Typical location of stasis dermatitis

Nikolsky sign

Lateral pressure applied on border of intact blister results in dislodgment of normal epidermis and extension of blister in SJS and TEN

SJS

SJS/TEN involving <10% BSA

SJS/TEN overlap

SJS/TEN involving 10-30% BSA

TEN

SJS/TEN involving >30% BSA

• Sulfonamides

• Allopurinol

• Nevirapine

• Antiepileptics (Lamotrigine, Phenytoin, Carbamazepine)

• Beta-lactams

• Oxicam NSAIDs

Drugs involved in SJS/TEN syndrome

Tzanck smear

Best initial test for herpes simplex and herpes zoster

Viral culture

Most accurate test for herpes simplex and herpes zoster

Thoracic area

Most commonly affected dermatome in herpes zoster

Trigeminal nerve

Most common single nerve involved in herpes zoster

First 72 hours of rash

Oral antivirals must be initiated within this period from the onset of rash

Malassezia furfur

Causative agent of tinea versicolor

Candidiasis

Presence of satellite lesions

Secondary bacterial superinfection

Most common infectious complication of varicella

Pneumonia

Most serious complication of varicella

Pityriasis rosea

Herald patch, Cigarette paper lesions, Christmas tree pattern at the back

Condyloma lata

Secondary syphilis

Condyloma acuminata

HPV or anogenital warts

Circle of Hebra

• Web spaces of fingers

• Flexor aspect of wrist

• Cubital fossae

• Anterior axillary folds

• Nipple

• Periumbilical fold

Area involved in scabies

Scabies

Burrows after mineral oil is applied

Melanoma

Most aggressive life-threatening dermatologic disease

Basal cell carcinoma

Most common skin cancer

Squamous cell carcinoma

Second most common skin cancer