Case 32: 5yo - Rashes

Question 1

define: blanching rash

Answer 1

blanching = the rash disappears when the overlying skin is stretched taut

blanching = superficial exanthem
nonblanching = deeper process (petechiae)

Question 2

describe: macule

Answer 2

flat, circumscribed disoloration
<1cm

ex. freckle

Question 3

describe:patch

Answer 3

larger, flat lesion of discoloration

>1cm

Question 4

describe:papule

Answer 4

elevated, circumscribed, solid lesion
<1cm

ex. mole (nevus)

Question 5

describe:plaque

Answer 5

broad, elevated lesion / confluence of papules

>1cm

Question 6

describe:vesicle

Answer 6

circumscribed, elevated lesion containing clear-colored fluid

Question 7

describe:bullae

Answer 7

LARGE circumscribed, elevated lesion containing clear-colored fluid

Question 8

describe:pustule

Answer 8

exudate (cloudy/yellow/green fluid)- containing lesion

Question 9

describe: nodule

Answer 9

circumscribed, elevated lesion that involves the dermis and may extend into subcutaneous tissue
(most is below the skin)

Question 10

describe: wheal

Answer 10

blanching, edematous, thin erythematous papule or plaque (+ rim of hyperpigmentation)

may be white –> pale –> red, and often appear/disappear over hours

Question 11

describe: telangectasia

Answer 11

dilation of superficial venules, arterioles, or capillaries visible on the skin

blanch with pressure

Question 12

describe: petechiae

Answer 12

tiny red/purple macules caused by capillary hemorrhage under the skin / mucous membrane

DO NOT blanch with pressure

Question 13

define: purpura

Answer 13

larger, purple lesion caused by bleeding under the skin

+/- palpable

DO NOT blanch with pressure

Question 14

define: scale

Answer 14

flakes of keratin that can be fine / coarse, loose or adherent

Question 15

define: scale

Answer 15

dried remains of serum / blood /pus overlying involved skin

Question 16

define: fissure

Answer 16

linear, often painful cleavage in the skin surface

Question 17

define: erosion

Answer 17

slightly depressed lesion where all/part of epidermis is lost

DOES NOT extend into underlying dermis, so healing occurs w/out scar formation

Question 18

define: ulcer

Answer 18

DEPRESSED lesion extending into dermis/subcu tissue

MAY lead to scar formation b/c so deep

Question 19

define: excoriation

Answer 19

traumatized, superficial loss of skin (usually linear), caused by scratching / rubbing

Question 20

acute urticaria

• define:
• pathophysiology:
• hx:
• dx:
• tx:

Answer 20

HIVES

• define: rash that comes and goes == change as you watch
• pathophysiology: allergens (drugs, food, pollen, viruses, temp) –> histamine release
• hx: FHx, PHM of atopic hx (atopic dermatitis, asthma, allergic rhinitis)
• dx: blood test / skin scratch testing for specific allergen
• tx:
  (1) avoid suspected allergens, stay cool and dry (out of the heat)
  (2) antihistamines (sedating-diphenhydramine; nonsedating-hydroxyzine, loratidine, certirizine)
  +/- oral prednisone (2nd line)

Question 21

stages of acne

==> how to treat them

Answer 21

1) Mild: COMEDONES = open (blackheads); closed (whiteheads)
==> OTC benzoyl peroxide (gel, skin wash)
==> topical retoinoids –> normalize follicular keratinization

2) Moderate: papules and pustules = inflamed, to larger erythematous lesions; + scarring
==> OTC benzoyl peroxide 
\+ topical clindamycin/erythromycin
\+/- oral doxycycline, tetracycline
\+/- OCPs (female)

3) Severe: nodulo-cystic acne; ++ scarring
==> oral isotretinoin

Question 22

acne triggers

Answer 22

• Make-up (unless noncomedogenic)
• Mechanical factors such as manipulation)
• Occlusion, as occurs with some sports gear
• Overzealous cleaning

Question 23

chronic nickel contact dermatitis

• define:
• pathogenesis:
• dx:
• tx:

Answer 23

• define: allergic contact dermatitis, usually in distribution of offender
  ==> mostly irritated and lichenified; hyperpigmented, cracking.
• pathogenesis: type 4 delayed hypersensitivity: sensitization ==> 2nd exposure (24-72h after first contact) ==> development of rash after SKIN BARRIER DAMAGE
  ==> can occur despite prior tolerance
• dx: if difficult to control = “patch testing” to evaluate for nickel / other allergen causing the rash
• tx: rash resolves within days to weeks of avoidance
• during healing = emolient (vaseline) / skin lubricating cream (aquaphor, eucerin)
  +/- medium-potency topical steroid ointment BID x2w

Question 24

impetigo

• cause:
• most common site:
• tx:
• complications:

Answer 24

• cause: Staph aureus, Strep pyogenes
• presentation: lesion seemed “weepy” and had honey-colored crusts
• most common site: below nares d/t rubbing and colonization (esp. Staph aureus)
• tx: topical mupirocin
• complications (d/t MRSA): abscess formation

Question 25

acute contact dermatitis

• define:
• pathogenesis:
• dx:
• tx:

Answer 25

• define: irritant / allergic (poison ivy, poison oak, poison sumac) or topical antibiotic
  ==> vesicles, edema, erythema; VERY pruritic
• pathogenesis: type 4 delayed hypersensitivity: sensitization ==> 2nd exposure (24-72h after first contact)
• dx: distribution
• tx: 1% hydrocortisone / triamcinolone (topical corticosteroid)

Question 26

topical steroids
- differentiate potency:
- differentiate ointment v. 
cream:
- how toipcal steroids work differently in children:
- ADR:

Answer 26

• differentiate potency:
  1) MILD (class 6,7): hydrocortisone acetate 1%
  2) INTERMEDIATE (class 4,5): triamcinolone acetonide 0.1%
  3) POTENT (class 2,3): betamethasonedipropionate 0.05%
  4) SUPER POTENT (class 1): clobetason propionate 0.05% [1000x more powerful v. hydrocortisone]
• ointment = more effective skin penetration ==> eczema
• ointment/cream = when penetration is not important ==> psoriasis
• how topical steroids work differently in children = infants absorb MUCH MORE medication thru skin v. adults (and esp. with occlusive dressing like a diaper)
• ADR: skin atrophy, telangiectasias, hypopigmentation, suppression of HPA
• even low-potency topical steroids over long periods of time, over large areas of body
• -> esp. on face/genitals

Question 27

pediculosis capitis

• define:
• pathogenesis of spread:
• is there a role for prophylaxis if a friend has it?
• tx:

Answer 27

HEAD LICE

• pathogenesis of spread: close personal contact, sharing of belongings
• lice cannot live away from host for >26h, and newly born nymphs need to feed immediately
• nits are firmly attached to hair shaft (at base) = 1-2mm from scalp
• NO NEED for prophylaxis == b/c treatment itself is irritating
• tx:
  1) DO NOT share belongings such as hats, coats, combs, and barrettes
  2) comb through wet hair with fine-toothed comb
  3) wash in hot water / dry in high heat - beeding, stuffed animals, hats, combs, brushes
  4) seal unwashable items in airtight bag

1) 1% permethrin lotion, 2-3x weekly
2) benzyl alcohol 5% (for kids >6mo), malathion 0.5% (for kids >2yo), as 2nd line

Question 28

why is lindane no longer used for head lice treatment?

Answer 28

• s/e of neurotoxicity

- widespread resistance

Question 29

Scabies

• cause:
• pathogenesis of spread:
• location:
• presentation:
• complications:
• dx:
• tx:

Answer 29

• cause: Sarcoptes scabiei
• pathogenesis of spread: significant close physical contact ==> burrows into skin and lays eggs
• location: wrists, elbows, fingers, toes; along waistband
  INFANTS = abdomen
• presentation: itching AT NIGHT, with 5-10mm curvilinear thread-like lesion (“burrow”); though infants may have just small papules w/out burrow
• dx:
  INFANTS:
  identification of mites, eggs, eggshell fragments or fecal pellets ==> multiple superficial skin samples (esp. @ burrows/papules and vesicles in site of burrows) via lateral scraping ==> under mineral oil with light microscope
• complications: secondary infections(impetigo, cellulitis), 2ary eczema, SUFFERING
• “post-scabetic itch” == can persist for a few weeks after treatment (d/t persistent inflammation from infestatino)
• tx:
  1) permetrhin 5% cream (once, x2w) for ALL AFFECTED FAMILY MEMBERS, all night for 8-12h, from neck down.
• INFANTS: from heairline down (avoid only eyes and mouth)
  2) after bathing, wash all bed linens and clothing worn during treatment
  3) for “post-scabetic itch” == moderate potency topical steroid + diphenhydramine

+/- oral ivermectin (2nd line) == if allergic / ineffective response to permetrhin
NOT for kids <15kg

Question 30

which, if any, of these are related to poor hygiene?

• head lice
• scabies

Answer 30

NEITHER

• just close contact

Question 31

ringworm

• define:
• cause:
• appearance:
• dx:

Answer 31

tinea corporis = superficial and easily trated fugnus
- cause: contact with animals
- appearance: annular, well-circumscribed, scalyplaque + raised border (“leading edge”) and brown/hypopigmented center
==> gradually enlarge, and coalesce
- mildly/not pruritic

• dx: clinically; KOH wet mount ==> classic branches and rod-shaped septated hyphae

Question 32

describe the other kinds of tinea
+ tx
- complications:

Answer 32

TINEA PEDIS = “athlete’s foot”
= more in young adults
==leading edge / scale + cracks and fissures between the toes
- tx = antifungal cream

TINEA CAPITIS = ringworm of the scalp
- tx = SYSTEMIC THERAPY (d/t  deeper hair folicles)
#1) griseofulvin, for 6-8w to kill it during replication phase (continue for full time to prevent recurrence)
#2) terbinafine, itraconazole (for resistant strains / can't tolerate griseofulvin)
- complications: "kerion" = significant allergic response  == inflamed, weeping, boggy lesions (tx = oral steroids), that go away once underlying fungal infection is treated.

TINEA VERSICOLOR = yeast form of the fungus(== Malassezia globosa, part of normal skin flora)
= +/- contagious, with underlying susceptibility. worsens with excess heat and humidity
== pink/brown/white lesions (depending on underlying skin color) + fine scale; can change color
- tx: selenium sulfide lotion
- complications: common recurrence; lasting pigment changes for months

Question 33

what happens if you treat a tinea infection with steroid creams?

Answer 33

it’s a FUNGAL INFECTION == but often looks like eczema

==> makes the infection worse, and the appearance atypical

Question 34

common warts v. molluscus contagiosum

Answer 34

WARTS = HPV

MOLLUSCUM CONTAGIOSUM = POXvirus

• smaller, smoother v. common warts
• central dimple = “umbilicated”

Question 35

common etiologies of diaper rash
==>
- presentation:
- treatment:

Answer 35

IRRITANT DERMATITIS
==> urine/stool (esp. diarrhea); prolonged exposure to moisture, friction, and digestive enzymes
- presentation: irregular areas of erythema + skin macertaion on convex surfaces of skin;
SPARES creases
- treatment: clean and dry (+ zinc oxide as barrier against urine and feces)

DIAPER CANDIDIASIS
==> fungal infection with moistness
- presentation: erythematous papules –> confluent, bright red papules, surrounded by more erythematous papules (“satellite” lesions)
- treatment: nystatin cream; (OLDER = miconazole, ketoconazole)

BACTERIAL INFECTION
==> group A strep
PERIANAL AREA
- presentation: can have honey-combing --> +/- cellulitis, bacteremia
\+ irritability; streak of blood in stool
- treatment: oral antibiotics

Question 36

most common cause of diaper rash

Answer 36

irritant dermatitis

Question 37

uncommon etiologies of diaper rash ==presentation of another illness
- what are some red flags?

Answer 37

INFLAMMATORY CONDITIONS
- seborrhea

RED FLAGS = irritability, growth problems, fevers, systemic sxs

NUTRIENT DEFICIENCY

• zinc deficiency
• acrodermatitis enteropathica
• malabsorption (cystic fibrosis)

LANGERHANDS CELL HISTIOCYTOSIS ==> lesions are crusty, weepy +/- bleeding

• NO improvement with steroids / antifungals
• dx = skin biopsy

Question 38

focused hx questions for a rash

Answer 38

• duration
• rate of onset
• location
• associated sxs
• family hx of similar sxs
• whether the pt has any allergies
• any new exposures
• any prior treatments (e.g. diphenhydramine) ==> (1) can change how the lesion looks; (2) if it worked

Question 39

key findings in diagnosis of allergic reaction

Answer 39

• Fhx, PMH of atopy
• recurrent rapid onset and resolution of rash ==> acute, repeated response to some sort of trigger
• pruritis (d/t histamine release from mast cells during allergic inflammation) == r/out viral exanthems
• hx of therapeutic response to antihistamine administration

Question 40

diffdx RASH

• appearance:
• epidemiology:
• cause:
• pathophysiology:

Answer 40

URTICARIA (type 1 hypersensitivity)

• appearance: intensely pruritic, circumscribed, raised, erythematous wheal + central pallor [individual lesions last 12-24h] ==> can coalesce into larger lesions –> continually change (various stages of “healing”)
• epidemiology: 15%
• cause: sometimes none; otherwise = drug, food, insect sting, infection
• pathophysiology: mast cell histamine release

PAPULAR URTICARIA

• appearance: PRURITIC, papular, 3-10mm in diameter; acute/recurrent/chronic
• epidemiology: COMMON
• cause: inset bites
• pathophysiology: histamine release

STREPTOCOCCAL INFECTION

• appearance: “scarlet fever” rash == fine, erythematous, sandpaper-like rash ESP. at skin creases
• cause:Strep pyogenes
• pathophysiology: d/t toxins; can cause urticaria.

ERYTHEMA MULTIFORME

• appearance: symmetrical rash; dusky red macules –> sharply demarcated wheals –> target-like lesions (can be mucosal), lasting for 1-3w [NOT WAXING/WANING]
• cause: HSV, meds
• pathophysiology: acute hypersensitivity syndrome

DRUG ERUPTION

• appearance: urticarial
• cause: opiates, NSAIDS
• pathophysiology: Type 1 hypersensitivity, or non-immunologic triggers of mast cell release

ROSEOLA

• appearance: after fever –> pink, maculopapular rash on trunk –> face/extremities
• cause: HHV6
• pathophysiology: viral exanthem, 3-days POST febrile illness

ERYTHEMA INFECTIOSUM (fifth disease)

• appearance: “slapped-cheek” –> reticular/lacy erythematous rash on trunk and extremities
• cause: Parvovirus B19
• pathophysiology: 3-5-days POST febrile illness

ERYTHEMA MIGRANS

• appearance: site of tick bite (>48h latch) = red papule –> large erythematous, annular patch
• cause: Lyme dz ==> early, localized

Question 41

common rashes in an infant

• appearance
• location

Answer 41

HEAD
SEBORRHEIC DERMATITIS ("cradle cap")
-appearance = erythematous plaque + fine-thick, greasy yellow scale
- location = scalp, ears, neck and diaper area

BODY
ECZEMA (ATOPIC DERMATITIS) + PMH atopic diathesis
-appearance = pruritic, erythematous, scaling plaques
- location = body, posterior scalp; extensor surface

PSORIASIS

• appearance = MORE erythematous, THICK non-waxy scale; more defined borders
• location = extensor surface

DIAPER
CANDIDAL RASH (peak @ 7-10mo)
-appearance = area of erythema + erythematous papules and plaques + satellite lesions
- location = inguinal region

Question 42

difference between seborrheic dermatitis and atopic dermatitis v. psoriasis

Answer 42

SEBORRHEIC DERMATITIS (yellow, greasy scale) and ATOPIC DERMATITIS (redder, with light scale on extensor surfaces)

PSORIASIS

• MORE erythematous, THICK non-waxy scale; more defined borders v. seborrheic dermatitis
• THICKER plaque, v. atopic dermatitis

Question 43

diffdx for pustular conditions
==> cause
- description:
- location:
- tx:

Answer 43

STAPHYLOCOCCAL FOLLICULITIS (furunculosis)

• description: looks like nodular / cystic acne
• location: below waist; groin area

ACNE VULGARIS ==> d/t (1) keratinous material, (2) excess sebum (d/t androgenic influence) ==> plugging pilosebaceous gland ==> superinfection with Propioniobacterium acnes

• description: comedones / erythematous / cystic-nodular
• location (SEBACEOUS GLANDS) = neck, face, chest, upper back, upper arms

HIDRADENITIS SUPPURATIVA ==> occlusion of apocrine follicular units - sweat glands (NOT PILOSEBACEOUS UNITS)

• description: pustular lesions
• location: (women) axillae, groin, inframammary areas; (men) perineal/perianal

ROSACEA ==> in adults, older adolescents (“early form”); worse with ETOH, spicy food, temp extremes, and stress

• description: inflammatory papules, micropustules, redness (NO COMEDONES)
• location: malar and nasal surfaces
• tx = topical metronidazole

PERIORAL DERMATITIS ==> variant of rosacea in adolescents

• description: erythema, scaling, papules/pustules (NO COMEDONES)
• location: around mouth, nose, eyes
• tx = topical metronidazole

Question 44

differentiate acne vulgaris v. hidradenitis suppurativa?

Answer 44

acne vulgaris == plugged pilosebaceous units
= more in face, chest, upper back

hidradenitis suppurativa == plugged apocrine follicular units (sweat glands)
= more in crease/folds

Question 45

differentiate acne vulgaris v. rosacea/perioral dermatitis

Answer 45

acne vulgaris = + comedones

rosacea/perioral dermatitis = NO comedones

Question 46

diffdx of ringworm (tinea corporis)
==> cause/ worsening
- description:
- location:

Answer 46

ringworm == annular, leading scale

NUMMULAR ECZEMA

• description: coin-shaped lesions; annular and scaly appearance
• location: legs, buttocks

PSORIASIS

• description: erythematous papules and plaques with THICK silver scale; annular
• location: extensor surfaces

PITYRIASIS ALBA ==> worse with sun exposure d/t tanning of surrounding skin (= decreased # of active melanocytes + #, size of melanosomes)

• description: hypopigmented patches, 0.5-5cm with well-defined, irregular borders and fine scale
• location: face, neck, upper trunk, and proximal extremities
• • similar to tinea versicolor **

PITYRIASIS ROSEA

• description: (1) “herald patch” (scaly plaque with raised border) + scaly papules and plaques in “christmas tree” distribution
• location:back and trunk, following skin cleavage; + upper thighs and groin

Question 47

what are the limitations with use of topical / oral retinoids for severe acne

Answer 47

• 2 forms of contraception
• use retinoinds at night (==> d/t photosensitivity and risk of severe sunburn)
• NOT at same time as bezoyle peroxide (b/c inactivates tretinoin)
• apply to DRY skin= otherwise will be very irritating with the wetness

== expectant: isotretinoin can make acne transiently look worse

Question 48

treatment of warts

what else have they been used in the treatment of?

Answer 48

2/3 spontaneously resolve in 2y

treatment depends on location, severity, and patient cooperation

1) Salicylic acid topical (qd)
2) duct tape ==> by occlusion and irritation of skin –> activate immune system == [for small, unobtrusive area]
3) Liquid nitrogen == in older kids, adults (faster, but not as effective as salicylic acid)
4) cantharidin == blistering at site of wart (1x), as combo with other agents
5) Candidal antigen therapy == VERY EXPENSIVE
6) curettage == s/e significant scar, recurrence

also used in the treatment of molluscum contagiosum (except duct tape)

Question 49

diffdx to urticaria

Answer 49

• papular urticaria
• streptococcal infection
• erythema multiforme
• drug eruption

Question 50

treatment of SEBORRHEIC DERMATITIS (“cradle cap”)

Answer 50

1) baby oil and small brush to remove the scales
2) frequent gentle baby shampoo +/- ketoconazole (around head and ears)
3) low-potency topical steroid cream (hydrocortisone)

Question 51

what is this in an adult? 
SEBORRHEIC DERMATITIS ("cradle cap")

treatment

Answer 51

Malassezia (fungus)

- tx = ketoconazole cream

Question 52

What diagnoses do you consider when you first see a patient with pustules on any part of his or her body?

 Multiple Choice Answer:
A		Eczema	
B		Staphylococcal folliculitis/furunculosis	
C		Pseudofolliculitis	
D		Acne vulgaris	
E		Erythema nodosum	
F		Hydradenitis suppurativa	
G		Rosacea	
H		Perioral dermatitis

Answer 52

Staph folliculitis
Acne vulgaris
hydradenitis suppurativa
rosacea
perioral dermatitis

pseudofolliculitis == papules (NOT PUSTULES)

Question 53

describe: pseudofolliculitis

Answer 53

papules (NOT PUSTULES)

• location: in the beard area
• pathophysiology: hair grows out of the follicle and, when shaved closely, often grows back in to the surrounding skin, causing irritation and inflammation

NOT acne –>b/c inflammation adjacent to hair follicles

Question 54

describe: erythema nodosum

Answer 54

nodules (NOT pustules)
== hypersensitivity rxn = red, tender, nodular lesions on pretibial surface of legs
- cause: infections, drugs, and inflammatory bowel disease.

Question 55

systemic acne treatments for moderate and severe acne

Answer 55

1) tetracyclines = doxycycline and minocycline –> s/e = [D] = photosensitivity, esophagitis, dental staining in <8yo, tetatogen, pseudotumor cerebri; [M] = vertigo, pseudotumor cerebri, skin pigmentation, lupus-like
==> mod and severe

2) OCPs (esp with low androgenic estrogen) - for females
==> moderate

3) oral isotretinoin == reduce sebum secretion; anti-inflammatory –> s/e = depression, hyperTG, hepatitis, decreased night vision, photosensitivity, teratogenicity
==> severe nodulocystic

Question 56

treatment for poison ivy exposure

Answer 56

within 30 min == wash with soap and water or dish detergent

1) topical steroids, oral antihistamines == for rash and itching
2) oral steroids for 10-14d (+taper) == for widespread / increasingly large rash; need extended period d/t risk of rebound rash if insufficient dose

Question 57

What are additional differential diagnostic possibilities for the tinea infections we have been talking about?

 Multiple Choice Answer:
A		Nummular eczema	
B		Contact dermatitis	
C		Impetigo	
D		Psoriasis	
E		Pityriasis alba	
F		Pityriasis rosea

Answer 57

nummular eczema
psoriasis
pityriasis alba
pityriasis rosea

Question 58

best treatment for warts

Answer 58

OTC salicylic acid (topical)

Question 59

Which of the following systemic illnesses commonly have diaper rash as one of the features?

 Multiple Choice Answer:
A		Henoch-Schonlein purpura (HSP)	
B		Zinc deficiency	
C		Melanoma	
D		Langerhans cell histiocytosis	
E		Irritable bowel syndrome	
F		Kawasaki disease

Answer 59

zinc deficiency
langerhands cell histiocytosis

HSP and Kawasaki = can start with rash in genital / buttocks area, but NOT diaper distribution

Question 60

A 3-year-old male presents to clinic with an annular, well-circumscribed, scaly plaque with a raised erythematous border and central hypopigmentation on the left thigh. The mother reports that the lesion is highly pruritic and that the patient has been exposed to other children with a similar rash at day care. Upon further examination, a similar lesion with boggy borders is also found on the posterior aspect of his scalp. Which of the following is the most appropriate treatment for this child’s problem?

 Single Choice Answer:
Please select one answer.  
A		Topical clotrimazole	
B		Hydrocortisone 1% cream	
C		Oral prednisone	
D		Oral griseofulvin	
E		Selenium sulfide shampoo

Answer 60

D

L thigh
posterior of scalp

no difference in color == not versicolor

exposure== likely infectious? (tinea capitis)

Topical antifungals are not usually successful in treating tinea capitis, because the infected hair follicles are deep within the scalp. Systemic griseofulvin is the first choice for the treatment of tinea capitis

Question 61

A 3-year-old child is found to have a dry, pruritic rash on his face. Physical exam is notable for confluent areas of erythema and scaling. There are mild excoriations surrounding some areas and mild lichenification of the extensor surfaces of both elbows. What is the next best step in management of this child’s problem?

 Single Choice Answer:
Please select one answer.  
A		Oral clindamycin for 5 days	
B		Changing detergents	
C		Topical clotrimazole	
D		Topical steroids and emollients	
E		5% permethrin cream

Answer 61

D

extensor surfaces = psoriasis
+ scale

“silvery”?
or atopic dermatitis

== treat both similarly with topical steroids

Atopic dermatitis most often presents with dry, itchy skin in addition to erythema, scaling, vesicles, or lichenification in skin flexures. Treatment consists of emollients and topical corticosteroids.

Question 62

A 10-year-old boy presents to his pediatrician with a history of hypopigmented non-pruritic “dots,” mostly located on his face and neck. His mother complains that lesions get worse during the summer when her son plays outside. On exam, they are slightly scaly, hypopigmented lesions approximately 0.5 cm in diameter. What is the most likely etiology of his rash?

Single Choice Answer:
Please select one answer.
A A pox virus
B Hyperproliferation of keratinocytes
C S. pyogenes and S. aureus
D Decreased number of active melanocytes and decreased number and size of melanosomes
E Ingrown hairs with resultant inflammation

Answer 62

D

heat-activated
sounds like tinea versicolor

. Pityriasis alba, common in children 3 to 16 years of age, presents as hypopigmented macules. They most often occur on the face, neck, trunk, and extremities. They have irregular borders, can vary in size, and may have a slight scale. Lesions may become more noticeable after sun exposure because of tanning of the surrounding skin. The etiology of this disorder is unknown, but ultrastructural examination of epidermal cells reveal decreased number of active melanocytes as well as decreased number and size of melanosomes.