Dermatology Take Home Quiz Answers

1.  Psoriasis

a.  What does the rash of psoriasis look like and where is it located?

Red, well-demarcated plaques covered with dry, thick, silvery scales. The lesions tend to be located on the extensor surfaces of the extremities, the scalp, and the buttocks. Thickening and fissuring of the skin of the palms may also be seen.

b.  How might psoriasis present in infancy?

Persistent diaper dermatitis

c.  What are the common nail findings in psoriasis?

Reddish-brown psoriatic plaques in the nail bed (oil drop changes), surface pitting and distal hyperkeratosis

d.  Describe Koebner phenomenon and Auspitz sign.

Koebner phenomenon – psoriatic lesions are induced at sites of local injury

Auspitz sign – when the psoriatic scale is removed, small bleeding points are seen. This is the hallmark of psoriasis

e.  What is guttate psoriasis and how is it different from typical psoriasis?

Drop-like psoriatic lesions that are found scattered all over the body. It may occur after a GAS infection.

2.  Compare and contrast Erythema Toxicum Neonatorum and Transient Neonatal Pustular Melanosis. Be sure to include onset, description and microscopic findings.

Erythema Toxicum Neonatorum – lesions typically begin 24-48h after birth, lesions have intense erythma with a central papule or pustule that is 2-3mm in diameter, the erythema is large, a smear of material from the pustule will reveal numerous eosinophils, fading occurs within 5-7 days

Transient Pustular Melanosis – presents at birth, 1-2mm vesiculopustules or ruptured pustules that disappear at 24-48h leaving a pigmented macule with a scale, a smear of material from the pusule will show neutrophils, the hyperpigmentation takes 3 weeks to 3 months to fade

3.  Which of the following have the potential for malignant transformation? (Bolded are correct)

  1. Congenital Nevomelanocytic Nevi, Pyogenic granuloma, Nevus sebaceous (although rare), Infantile hemangiomas, Nevus simplex, Blue nevus, Spitz nevus

4.  How can you tell the difference between the hypopigmented lesions of vitiligo and ash-leaf spots?

Vitiligo will result in partial to complete loss of pigmentation. Ash-leaf spots are not totally depigmented. The lesions of vitiligo will usually be seen around the eyes, mouth, genitals, elbows and hands. Ash-leaf spots more typically have a truncal distribution. While both will enhance with a Wood’s lamp examination, the enhancement with vitiligo is much more dramatic.

5.  Describe the hair loss in the following conditions.

  1. Alopecia Areata – round or oval patches of hair loss that may be located anywhere on the scalp, eyebrows, lashes or body and may occasionally be diffuse or generalized. There is a lack of inflammation but the presence of short easily plucked out hairs at the margins of the patch. The hair shaft narrows just before the point of entry into the follicle.
  2. Trichorrhexis Nodosa – easy hair shaft breakage, brittle, short hairs with fraying of distal ends on microscopy
  3. Friction Alopecia – most commonly on the posterior scalp of infants from rubbing
  4. Traction Alopecia – hair loss at the sites of excessive traction due to ponytails, pigtails, braids or cornrows
  5. Trichotillosis – bizarre patterns of hair loss often in broad, linear bands on the vertex or sides of the scalp (non-dominant hand), short-broken off hairs with different lengths (never completely bald)

6.  List at least 5 skin findings associated with atopic dermatitis.

Keratosis pilaris, pityriasis alba, xerosis, lichenification, ichthyosis vulgaris

7.  Describe the approach to treatment of SJS/TEN.

Treatment: IVIG and supportive care. Should transfer to burn center, especially in TEN. Treat the following complications:

  Ophtho: Corneal scarring, Lid scarring: ectropion

  FEN: Dehydration, Malnutrition, Electrolyte imbalance

  ID: Superficial infection, Sepsis

  Steroids relatively contraindicated

  GI symptoms

8. Describe the signs/symptoms associated with serum sickness-like reaction.

Urticarial lesions: Relatively nonpruritic, Target or serpiginous (gyrate)/ Periarticular swelling: Migratory/ Stocking-glove angioedema: Painful/ Facial edema/ Fever

9. What is the cause of papular urticaria?

Hypersensitivity to insect bites, usually in a young child. May be mosquitoes, bedbugs, fleas, etc.

10. Describe two physical exam findings that aid in distinguishing plantar warts from other lesions of the sole.

Pinpoint black spots (thrombosed capillaries). Interruption of dermatoglyphics.