DERM Flashcards
A lice egg is called a nit.
True or false.
False!
Trick question.
The eggs are small, about 1/3 the size of a sesame seed. Nits are the empty case left after the eggs hatch and are easier to see, and found further down the hair shaft.
How many days does it take for lice eggs to hatch?
9 -10 days
How are head lice transmitted?
Head to head contact. They cannot jump or fly.
What is the wet-combing method of head lice treatment?
Copious amounts of conditioner onto wet hair (stops the little bastards from moving), and combing through all the hair. Wipe the comb onto a paper towel between stroked.
Wet comb every 4 days for at least 2 weeks. If still lice, continue combing every 4 days until no more lices. Louses? Lice.
Note: RXFiles reports low success rates with this method.
When would you recommend someone repeat a chemical treatment for head lice?
In 7-10 days.
If one of the four 1st-line head lice treatments are not effective, what is the 2nd-line recommendation?
Try again with another 1st line tx.
As per RxFiles.
Name 2 of the 4 recommended medication used as 1st line tx for pediculosis capitis. (as per RxFiles)
Permethrin (NIX)
Pyrethrins/Piperonyl Butoxide (R&C)
Isopropyl Myristate (Resultz)
Dimethicone (NYDA)
What are some common presentations of pediculosis corporis (body lice)?
Rash may be limited to linear excoriations on the trunk and neck along with postinflammatory hyperpigmentation, sometimes with thickening or lichenification.
Occasional presence of hemorrhagic puncta or wheals from fresh bites. Rashes primarily located around the waist and in the axillary folds.
What is the recommended tx for body lice? (as per Marcela’s slide)
P. Corporis: Thorough bath. Infested clothing and bed linen-heat washed (149°F or hotter), dry cleaned, or discarded. Ironing clothing with particular attention to the seams will also kill lice on fabrics. If nits are persistent, prescribe a single 8 to 10-hour application of permethrin 5% cream to the entire body.
What is the recommended tx for pubic lice? (as per Marcela’s slide)
P. Pubis: First line is topical permethrin 1% or a product containing pyrethrins with piperonyl butoxide. Treatment should be repeated after 9 to 10 days if lice remain. Advisable to screen for STIs. Sexual partners of individuals with pediculosis pubis should be treated simultaneously. Bedding and clothing should be laundered in hot water.
Name some risk factors/populations more likely to develop thrush (oropharyngeal candidiasis)?
-infants
-older adults who wear dentures
-smoking
-poor oral hygiene
-patients treated with antibiotics, chemotherapy, or radiation therapy to the head and neck
-those with cellular immune deficiency states, such as AIDS
-patients with xerostomia and those treated with inhaled glucocorticoids for asthma or rhinitis are also at risk
Although many people with thrush do not present with any symptoms, some complaints may be:
-a cottony feeling in the mouth
-loss of taste
-sometimes pain on eating and swallowing
-patients with dentures often have pain when they try to wear their dentures
Is nystatin safe in pregnancy and lactation?
Yes as per RxFiles
What is the tx for oral thrush?
Nystatin liquid 5 ml QID for 7 days or until 2 days after improvement.
Infants: 1-2 ml QID. May swab 0.5 ml onto tongue
What is this:
Common in moist skin folds.
Results in tender, burning, pruritic areas (may develop satellite lesions)
Candidal Intertrigo
What is the common tx recommended for candidal intertrigo?
Nystatin topical cream
Is it safe to swallow nystatin liquid?
Totes. Tell your patients to swish and swallow.
What does ‘atopic’ refer to?
What conditions does this include in kids?
refers to having a sensitivity to allergens such as environmental (extreme weather changes, dust, pollen etc), animals (dogs, cats), food (dairy, wheat, nuts, fish), irritants (detergents, soaps, creams etc), and stress
Atopic conditions commonly seen in children and adolescents: asthma, allergic conjunctivitis, allergic rhinitis, and atopic dermatitis (eczema)
What is the difference between atopic and contact dermatitis? They are both kinds of _______.
- Both fall under the umbrella of eczema and present with similar symptoms
- they have different causes. Typically, a person inherits atopic dermatitis, while contact dermatitis occurs following exposure to an external factor that triggers a reaction
Atopic dermatitis aka _____
Atopic eczema
**The most common inflammatory skin disease worldwide
Who typically gets atopic dermatitis?
Those with other atopic conditions (asthma, hay fever, food allergies)
When does atopic dermatitis usually present?
** most common in children
-usually starts in infancy, affecting up to 20% of children. Approximately 80% of children affected develop it before the age of 6 years.
Although it can settle in late childhood and adolescence, the prevalence in young adults up to 26 years of age is still 5–15%.
What causes atopic dermatitis?
Results from a complex interplay between environmental and genetic factors
Triggers (according to Toronto Notes) include:
* Irritants (detergents, solvents,
clothing, water hardness)
* Contact allergens
* Environmental aeroallergens (e.g.
dust mites)
* Inappropriate bathing habits (e.g. long
hot showers)
* Sweating
*Changes to weather
* Microbes (e.g. S. aureus)
* Stress
Clinical manifestations of atopic dermatitis
red, weeping/crusted (exudative) and may have blisters (vesicles or bullae)
Over time the dermatitis becomes chronic and the skin becomes less red but thickened (lichenified) and scaly. Cracking of the skin (fissures) can occur.
- possibly secondary bacterial infections
- itchy itchy itchy
Time course of atopic dermatitis
The clinical phenotype of atopic dermatitis can vary greatly, but is characterized by remission and relapse with acute flares on a background of chronic dermatitis.
How does infantile atopic dermatitis present?
- Most often on face & scalp, extensor surface
- Erythematous, pruritic, sale, crusted lesions (without or without vesicles and serous exudate)
Extra notes from DermNet:
- At or shortly after birth, atopic dermatitis may initially present as infantile seborrhoeic dermatitis involving the scalp, and the armpit and groin creases.
- The skin often feels dry and rough. With time the face, especially the cheeks, and flexures become involved.
How does atopic dermatitis distribution change as children enter toddlerhood and early childhood?
2-16 years old
*most often affects flexor surfaces and extremities (creases of inner aspect of elbows, wrists, ankles, neck)
From DermNet:
- With crawling, the extensor aspects of the elbows and wrists, knees and ankles are affected.
- The distribution becomes flexural with walking, particularly involving the antecubital and popliteal fossae (elbow and knee creases).
- Dribble and food can cause dermatitis around the mouth and chin. Scratching and chronic rubbing can cause the skin to become lichenified (thickened and dry), and around the eyes can lead to eye damage
The Dennie Morgan fold is a clue to dermatitis in kids. What is it?
A Dennie-Morgan fold is a fold of skin under the lower eyelids
- due to chronic eyelid dermatitis
What is the patho of atopic dermatitis?
IgE mediated immune response (Type 1 hypersensitivity reaction)
Basically the immune system is attacking the skin
T/F Atopic dermatitis is itchy
True! Itchy, dry skin.
What are the psychologic effects of atopic dermatitis?
Very common to cause depression and anxiety - screen for these!
Treatments for atopic dermatitis
ID and avoid any triggers
- avoid overheating
- dress in soft fabrics
- manage stress
- Frequent moisturizing to manage dry skin (particularly after luke warm bath): use ointments and creams with lower water content
- Keep short fingernails to avoid complications from scratching (especially in young children)
- Steroids, calcineurin inhibitors
- Antihistamines for itching
- Abx for secondary infections
What is the typical distribution of atopic dermatitis in adults?
- Localized lichenified plaques
- Flexural surface involvement
- uncommonly affects face, neck, hands
What is contact dermatitis?
- Inflammation of the skin after contact exposure to allergens/irritants (irritation can be mechanical, chemical, physical)
- Localized
- Exposure to foreign substances trigger immune response
- Most common form = irritant contact dermatitis
Common causes of contact dermatitis?
- Detergents, surfactants, extreme pH, organic solvents
- Plants with spines/irritant hairs
- Allergic contact dermatitis from: poison ivy or poison oak, nickel, fragrances, dyes
S&S of contact dermatitis
- Erythematous rash (can develop <72 hours after exposure)
- Vesicles/bullae/wheals occur at exposure site
- Glaze/parched/scaled presentation
- Scaling, hyperkeratosis, fissuring
- Itching favours allergic etiology, burning favours irritant etiology
What did Brenda really stress regarding the difference between atopic and contact dermatitis with regard to distribution?
Contact dermatitis will be localized to area of exposure (such as circumferential rash around wrist if caused by watch)
Treatment of contact dermatitis
- Pruritis: calamine lotion
- Mild topical corticosteroids (hydrocortisone)
- Oral antihistamine
- Allergic contact dermatitis: high potency topical steroid, oral corticosteroids, typical calcineurin inhibitors (tacrolimus/pimecrolimus), other forms of systemic immunosuppression
- Remove/avoid trigger
- Treat blistering: cold compress
- Avoid scratching
- Retain moisture/protect skin (such as zinc barrier cream)
- Possible phototherapy for allergic contact dermatitis
Urticaria aka ____
Caused by?
Hives/welts/wheals
What is tinea capitus?
A ringworm (dermatophyte) infection on one’s head.
How is hives described in proper derm terms?
What is it and how is it different from angioedema?
intensely pruritic, erythematous plaque
- Have pale, papular centers
- not painful unless scratched
clinical rash produced by capillary leak vasodilation and edema of the skin
Angioedema: extension of urticarial process deeper into the dermis, producing swelling
What is tinea corporis?
A ringworm infection on one’s body.
T/F Hives can persist for weeks or months without a known trigger
True! Can become chronic (defined as >6 weeks)
** individual lesions persist less than 24 hours…but new ones pop up or reocurr in same spot
What is tinea versicolor?
More accurately called pitryasis versicolor. Caused by the fungus Malassezia furfur, it is a common skin condition characterized by superficial scaly papules and circular plaques of varying colour (white, pink, brown) on the chest, back and shoulders.
What is the patho of urticaria?
-A reaction to epidermal mast cell release of histamine, prostaglandins, leukotrienes
-Occurs in sensitized patients on re-exposure to antigens in food, medications, supplements and insect venom
-Mast cells can also be activated independent of IgE mechanisms:
- Viral, bacterial, parasitic and fungal infections
- Collagen vascular disease
- Malignancy
- Endocrine disease
- Physical factors: heat, cold, pressure, sun, vibration
What is onychomycosis?
Tinea of the nails, caused by yeast or dermatophyte infection of the nail or nail bed.
T/F a urticarial rash is non-blanchable
F - they are blanchable
What is the recommended tx for diaper rash?
Apply antifungal underneath barrier cream until rash is resolved.
-Topical nystatin, clotrimazole, miconazole, or ketocanzole if rash is candidial or >3 days.
In taking a history for a patient with hives, what should we ask about?
History focus on exposure to
-drugs
-dietary changes
-new soaps/detergents
-environmental agents
-recent viral illnesses
What is the recommended tx for tinea capitis (scalp)?
What are some side effects to counsel about?
As per RXFiles, the drug of choice is oral terbinafine (Lamisil) x 4-8 weeks. May also prescribe selenium sulfide/ketoconazole shampoo 2-3x/week to decrease spread.
Common S/E of Lamisil: headache, GI upset, rash. Rare: alopecia
Very rare chance of liver injury but if you’re concerned: baseline LFTs and at 4-6 weeks.
Treatment of urticaria-
Identify and eliminate causative agent
-Avoid causes, or treat underlying cause if more serious etiology
-H1 and H2 receptor agonists
-Corticosteroids in severe/persistent cases
-Role for tricyclic antidepressants due to potent antihistamine effects
S&S of angioedema in contrast to hives?
No distinct rash, not pruritic
Tissue swelling, sense of tightness, sometimes pain
Risk factors for scabies?
Crowded conditions
Poor hygiene
Poverty
Malnutrition
Homelessness
Immunodeficiency.
- common in pediatric population
Scabies is caused by an infestation of what?
Sarcoptes Scabiei
(a mite)
Which bacteria are responsible for impetigo?
Staphyl aureus (approx 80% of cases)
Group A strep (approx 20% of cases)
Or a combination of the 2.
Note: Group B strep may cause impetigo in a newborn.
Scabies typically affects what areas of the body?
Webbing of fingers and toes, skin folds/creases (intertriginous areas) such as intragluteal fold, wasite, soles of feed, axillae, genitals
*not typically above neck except infants, elderly, and immunocompromised
How is scabies transmitted?
Direct contact
spread amongst sexual partners is common
**A brief handshake or hug does not usually allow for transmission unless the patient has crusted scabies
**Spread via fomites (clothing, towels, etc.) is very uncommon as the mite perishes within hours of leaving the host
What is the most common part of the body that you will find impetigo?
The face.
Patho of scabies
When is the itch worst with scabies?
Adult female burrows under the skin and lays 60-90 eggs. The eggs become adults after 2 weeks
Up to 2-6 weeks after infestation, immune response becomes sensitized to mite or scybala (mite feces), causing systemic pruritis and rash
In most individuals the rash is an allergic phenomenon, each eruptive papule may not actually contain mites
**Generalized itch
**itch worst at night
**Itch occurs within hours of subsequent re-infection
How long is a typical scabies burrow?
What is crusted scabies?
Characteristic burrrow is 3-10 mm long greyish/white line and can be difficult to see
Crusted scabies – extensive mite infestation resulting in thick, greasy yellowish scale and crusts over extremeties and trunk
What are some differentials to consider if your working diagnosis is impetigo?
Perioral dermatitis
Allergic contact dermatitis
Herpes simplex and herpes zoster
Pemphigus foliaceus and pemphigus vulgaris
Tinea infection
Treatment of scabies
Preferred product: permethrin cream – approved for infants 2 months and older
- Apply head to toe in infants and neck to toe in small children/adults
- Leave on for 8-12 hours, then rinse off
- Repeat after 1 week
Oral invermectin is also successful. Given as a 200mcg/kg dose, then repeated in 1 week
All affected household members should be treated simultaneously and bed linens/clothing washed in hot water
Seal items in plastic bag for 48-72 hours if can’t wash
What is the recommended tx for impetigo?
Topical therapy in less severe/localized cases: mupirocin 2% cream apply sparingly TID
Significant soft tissue infection or community outbreaks:
Cephalexin 50-100 mg/kg/day divided QID
Duration of therapy is usually 5-7 days.