Dermatology Flashcards
Pityriasis rosea
Acute exanthem, commonly affects children and young adults.
HHV6 and HHV7
Initial herald patch, followed by the development of a diffuse papulosquamous rash.
Alkali burns vs acid
Alkali burns causes liquefactive necrosis of involved tissues. Acid burns cause coagulation necrosis, which is slower in manifestation.
First-line treatment of acne rosacea.
Topical metronidazole
Erythropoeitic protoporphyria
Deficiency of the ferrochelatase enzyme, the final enzyme in the heme biosynthesis pathway.
Accumulation of protoporphyrin substrate.
Acute cutaneous photosensitivity as well as hepatobiliary disease.
The inheritance is termed “pseudodominant”, as both autosomal recessive and dominant forms have been identified.
Excruciating pain, redness, and swelling of the skin after short-term sun exposure. Blisters, erosions, and scarring are less common.
Oral beta carotene may reduce photosensitivity in some patients.
The diagnosis of vitiligo can be confirmed through?
Visualization of lesions under a Wood’s lamp, as hypopigmentation will fluoresces bright blue-white) due to accumulated biopterins
Porphyria cutanea tarda histologically
‘caterpillar bodies’ - linear, eosinophilic, periodic acid-Schiff–positive globules - found in the blisters and skin lesions
Basal cell carcinoma high risk lesions
Lesions larger than 6 mm in high risk areas (central face, nose, lips, eyelids, postauricular areas, hands, and feet) or larger than 10 mm on all other areas of the head and neck are considered high risk. Other high risk features include those with sclerosing, mixed infiltrative, micronodular, or basosquamous features, and those that are recurrent.
Should be treated with Mohs surgery.
Seborrheic dermatitis is associated with which diseases?
Parkinson disease and HIV
The most accurate test for tinea capitis?
the best initial diagnostic test is a KOH preparation but the most accurate is a fungal culture in Sabouraud liquid medium.
Porphyria cutanea tarda
caused by deficiency in uroporphyrinogen decarboxylase.
Fragile skin and photosensitivity, flaccid vesicles and bullae with hemorrhagic crusts on the dorsal hands, hypertrichosis of the face, and hyperpigmentation.
The urine may be dark due to increased urine porphyrins.
Common precipitants of flares include alcohol, estrogens, viral infections (HCV, HIV), iron overload, and dialysis in patients with chronic renal disease.
Management: avoidance of sunlight and known triggers, hydroxychloroquine and periodic phlebotomy can be beneficial.
Lichen sclerosus
Autoimmune
Causes white, itchy, wrinkled patches of skin.
It can affect the skin around the genitals and anus.
Itching, pain, or bleeding
Marjolin ulcers
After long term damage to the skin that prevents complete healing, such as gunshot wounds and burns, or damage due to peripheral neuropathy in diabetes or venous congestion in the lower extremities.
The transition of an old wound to a wound that starts ulcerating, bleeding, and growing more rapidly may be indications of transition to squamous cell carcinoma.
