2025 – PAGE 148 – DERMATOLOGY
(DOUBLE TAKE) ECTHYMA GANGRENOSUM
Ecthyma gangrenosum is usually a sign of a PSEUDOMONAS infection and possibly sepsis in an immunocompromised patient, especially LEUKEMIA! Look for a neutropenic patient with black, necrotic, ulcerative lesions with surrounding erythema and edema. These lesions are often located in the groin/diaper area.
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GRANULOMA ANNULARE
Granuloma annulare is a chronic skin condition with an annular (circular) lesion occuring under the skin’s surface. It may be slightly pruritic. There are no scales.
PEARL: This looks kind of like ringworm, but there is NO SCALING! Keep this in mind any time you see Tinea as an answer choice.
IMAGE: www.pbrlinks.com/GRANULOMA1
PITTED KERATOLYSIS
Pitted keratolysis is a condition in which there is pitted skin in areas of pressure. There will probably be a history of strong foot odor.
IMAGE: www.pbrlinks.com/PKERATOLYSIS1
(DOUBLE TAKE) DERMATOMYOSITIS
Dermatomyositis results in a heliotropic, violaceous rash in malar area. Gottron’s Papules (erythematous, shiny, pruritic papules over the metacarpals) may be present. Patients will have proximal weakness and possible telangiectasias near the nail folds. Diagnose with a MUSCLE BIOPSY. The CK LEVEL WILL BE HIGH. These patients can also get calcinosis cutis.
PEARL/REMINDER: Duchenne Muscular Dystrophy also has elevated CK levels.
IMAGE: www.pbrlinks.com/DERMATOMYOSITIS1
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IMAGE: (calcinosis cutis) www.pbrlinks.com/DERMATOMYOSITIS3
STEVENS-JOHNSON SYNDROME (SJS) and TOXIC EPIDERMAL NECROLYSIS (TEN)
Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are on a spectrum. They are differentiated by body surface area (BSA). SJS is diagnosed if < 10% of the BSA is involved, and TEN is the diagnosis if > 30% of body surface area is involved. Anything in between is called SJS/TEN. Look for bullae or erosions followed by hemorrhagic crusting. There may be severe blistering and a Nikolsky sign (separation of epidermis with firm pressure) or the presence of the Asboe-Hansen sign (spread of a blister laterally when pressure is applied). It is a full thickness rash similar to a burn. Skin lesions may look like a BULLSEYE or TARGET lesion, with the center described as DARK, DUSKY, or VIOLACEOUS. The target CAN be a blister or vesicle. At least two mucous membranes must be involved (most commonly the lips and eyes). If the eyes are involved, this is an ocular emergency!
MEDICATION ASSOCIATIONS: Aromatic seizure medications, penicillins, NSAIDS, and sulfa drugs. The rash usually occurs within 2 months of starting the medication.
MNEMONIC: Imagine Stevens and Johnson as two very arrogant hunters. They went TARGET shooting one day in an area that said, “Beware of BULLS.” They learned their lesson the hard way when a BULL came out of nowhere and did some target practice of his own.