DERM 07: Minor Fungal Skin Infections Flashcards
1
Q
What are tinea?
A
fungal infections (mycoses)/disease caused by skin-loving fungi called dermatophytes
2
Q
How are fungal skin infections typically classified?
A
by location
- tinea capitis: affects head
- tinea barbae: affects beard
- tinea faciei: affects face
- tinea corporis: affects body
- tinea manuum: occurs on hand
- tinea pedis: occurs on feet
- tinea cruris: affects groin area
3
Q
Dermatophytes
- What are the 3 genera?
- Is it part of normal flora?
- How is it spread?
- What layer of skin does it affect?
A
- 3 genera: trichophyton, microsporum, epidermophyton
- not part of normal flora
- typically spread from person-to-person (contagious), but can also spread from different carriers depending on species
- use dead keratin (main structural protein found in epidermis) as source of nutrition and growth
- only affect top layer of epidermis (stratum corneum), hair, and nails (contain keratin)
- does not invade living tissue and mucosal tissues (no keratin)
4
Q
Describe the pathogenesis of tinea infections.
A
- initiating event of fungal skin infections is exposure to dermatophyte (b/c not part of normal body flora)
- compromised skin barrier and potentially weakened defence system can increase risk of exposure, resulting in fungal infection
- skin is always rapidly turning over and replacing itself, therefore ability of fungus to grow at faster rate than skin is being shed determines size and duration of lesion of resulting infection
5
Q
What are the 4 types of exposure to dermatophytes?
A
- anthropophilic
- zoophilic
- geophilic
- fomites
6
Q
What is anthropophilic exposure to dermatophytes?
A
direct contact with humans
- most common mode of transmission
- ie. contracted from household members, daycare, contact sports
7
Q
What is zoophilic exposure to dermatophytes?
A
direct contact with animals
- ie. infected cat or dog
8
Q
What is geophilic exposure to dermatophytes?
A
direct contact with soil
- ie. farm workers may be at risk
9
Q
What is fomites exposure to dermatophytes?
A
indirect contact through fomites (inanimate object contaminated with infectious agents such as bacteria and viruses, which can transmit disease to individuals who come in contact with it)
- ie. in locker rooms, swimming pools, contaminated clothing, brushes, or doorknobs
10
Q
What are the risk factors for tinea infection? (4)
A
- exposure
- immunosuppression
- trauma to skin or nail
- optimal conditions for fungal growth
11
Q
Risk Factors for Tinea Infection
Exposure (2)
A
- concurrent fungal infection elsewhere on body – ie. tinea pedis leading to tinea cruris, tinea pedis leading to onychomycosis (fungal nail infection)
- going barefoot in public areas
12
Q
Risk Factors for Tinea Infection
Immunosuppression
A
certain risk factors decrease body’s ability to mount effective immune response to fungal skin infection
- advancing age
- diabetes
- HIV
- peripheral vascular insufficiency
- medications that cause immunosuppression
(monitor patients with these comorbidities closely)
13
Q
Risk Factors for Tinea Infection
Trauma to Skin or Nail
A
- wearing poor fitting footwear
- playing sports (ie. wrestling)
- injuries
- breakdown of skin barrier via increased moisture (ie. sweating)
14
Q
Risk Factors for Tinea Infection
Optimal Conditions for Fungal Growth
A
warm, dark, and moist conditions allow fungus to thrive:
- tropical or subtropical climates
- sweating or hyperhidrosis
- obesity (due to persistent contact between skin folds promoting moist environment)
- wet clothing
- occlusive clothing or shoes (ie. tight, made of nonporous/breathable material)
(non-pharmacological recommendations that eliminate risk factors for continued fungal infection are important part of patient care for these infections)
15
Q
What is the pharmacists’ patient care process?
A
- collect
- visually inspect dermatosis using precise terminology to describe rashes, SCHOLAR-MACS
- assess
- patient self-assessment
- clinical presentation
- diagnosis
- red flags and referrals
- plan
- goals of therapy
- non-pharmacological recommendations
- pharmacological treatment
- implement
- patient education
- follow-up (monitor and evaluate)
16
Q
Can pharmacists prescribe for tinea infections?
A
yes, if they can readily diagnose without imaging and lab tests
- most superficial fungal skin conditions can be diagnosed w/ history + physical exam
17
Q
What can physicians do for diagnosing tinea infections that pharmacists cannot?
A
can collect sample or order potassium hydroxide (KOH) test – dissolves keratin and allows visualization of fungal elements, but does NOT identify species (need culture or biopsy, which are only used for atypical presentations)
18
Q
Describe the distribution of tinea corporis (ringworm).
A
anywhere on trunk, limbs, or neck (usually on hairless areas)
19
Q
Describe the presentation of tinea corporis (ringworm).
A
- single or multiple small plaques (~1-5 cm) – annular (ring) with well-defined, bumpy, scaly, erythematous border, border may also contain pustules, papules, or vesicles
- may or may not present with itching or burning
- expands outwards as infection progresses
- may be acute or chronic (in terms of how fast it grows – either appear suddenly or develop more slowly over time)
20
Q
What is the expected age and demographics for tinea corporis (ringworm)?
A
- common in pre-pubertal children
- more common in men
- outbreaks often occur in close-contact athletes
21
Q
What are the differential diagnoses for tinea corporis (ringworm)?
A
- pityriasis versicolour
- impetigo
- seborrheic dermatitis
- psoriasis
- discoid eczema
- contact allergic dermatitis
- pityriasis rosea
22
Q
Describe the distribution of tinea cruris (jock itch).
A
- pubic area and upper inner part of thigh
- may see ring-like patterns on buttocks
- not often seen on scrotum, penis, vulva, around anus
23
Q
Describe the presentation of tinea cruris (jock itch).
A
- single or multiple large plaques – annular (ring) with well-defined, bumpy, scaly, erythematous border, border may also contain pustules and vesicles
- expands outwards as infection progresses
- typically bilateral/symmetrical
- itching and burning are common
24
Q
What is the expected age and demographics for tinea cruris (jock itch)?
A
- common in adults
- more common in men
- common in athletes
- overweight patients at greater risk
25
What are the differential diagnoses for tinea cruris (jock itch)?
- yeast infection
- psoriasis
- erythasma
- seborrheic dermatitis
26
What are the 3 common presentations of tinea pedis (athlete's foot) and what do they all have in common in presentation?
all asymmetrical and unilateral, usually itching, burning, and pain
- interdigital
- moccasin-like
- vesculobullous
27
What is the interdigital presentation of tinea pedis (athlete's foot)?
- affects web spaces between 3rd/4th and 4th/5th toes
- characterized by scaling, fissuring (cracks), and maceration
- may be malodorous
28
What is the moccasin-like presentation of tinea pedis (athlete's foot)?
- affects soles, heels, and sides of feet
- characterized by scaly, thickened, red or silvery- white skin
29
What is the vesiculobullous presentation of tinea pedis (athlete's foot)?
characterized by vesicles, pustules, and sometimes bullae in inflammatory pattern on soles with scaling
30
What is the expected age and demographics for tinea pedis (athlete's foot)?
- common in adults, mainly men and teenagers
- rare in children < 12 years old – referral
31
What are the differential diagnoses for tinea pedis (athlete's foot)?
- contact dermatitis
- psoriasis
- juvenile plantar dermatosis
- pitted keratolysis
- atopic dermatitis
- dyshidrotic eczema
- pachyonychia congenita
32
When should patients be referred? (3)
- unclear diagnosis
- severe clinical presentation
- further investigation or systemic therapy required
33
Describe an unclear diagnosis.
when clinical presentation of lesions is not typical, risk factors are absent, and true condition is in doubt:
- annular plaque is found on a different area of the body – tinea manuum, tinea barbae, and tinea capitis are beyond scope of pharmacists as they require systemic treatment (topical agents do not easily penetrate hair follicles or thick skin)
- annular rash is found on a mucous membrane – dermatophytes require keratin for growth, which is absent in mucosal tissue
- annular plaque also affects the genitalia – tinea cruris does not affect genitalia
- suspected tinea incognito – may occur if patient has used steroid cream (ie. OTC hydrocortisone products) for dermatophyte infection which can alter appearance of lesion,
34
Describe the presentation of tinea incognito.
lesions do not have raised margin, are less scaly, more pustular, more extensive, and more irritable compared to tinea corporis
35
Describe a severe clinical presentation.
- extensive (diameter > 5 cm) or widespread (multiple locations on body)
- seriously inflamed
- weeping (ie. unexpected blisters or purulent)
- excessive and continuous exudation
- debilitating, painful, or disabling
36
When is further investigation or systemic therapy required?
- age < 2 years with tinea corporis and tinea cruris
- age < 12 years with tinea pedis
- tinea infections of other locations such as tinea unguium (nails) for first time or tinea capitis (face, scalp)
- patient has related comorbidities – ie. peripheral vascular disease for tinea pedis
- patient is immunocompromised (higher risk of infections) – ie. uncontrolled or advanced diabetes, due to HIV or medication such as chemotherapy or corticosteroids
- signs of secondary bacterial infection (oozing purulent material)
- patient has signs of system illness (fever, malaise, or both) – ie. person might have advanced tinea pedis, which increases risk of cellulitis, which might then progress to bacteremia and cause symptoms of systemic illness
- no improvement or worsening of symptoms after 1 week of initial treatment
37
What are the goals of therapy for tinea infections?
- resolve signs and symptoms of infection
- eradicate infection
- limit spread (to other parts of body and to other individuals)
- reduce risk of secondary complications (increased moisture may trigger bacterial overgrowth) – ie. cellulitis in tinea pedis, majocchi granuloma in tinea corporis
38
What are some non-pharmacological recommendations for tinea infections?
- skin should be kept dry – antiperspirants and non-medicated powders can help, NO cornstarch (source of nutrition for fungi), dry between toes, cotton balls to separate toes
- wear loose or non-occlusive clothing/footwear – made of natural fibres (cotton), sandals
- avoid rubbing or itching lesions – can harm skin surface and cause infection to spread
- prevent spread of infection – avoid contact/sharing items, separate laundry, no barefoot
- have pets examined by veterinarian for fungal infection that could be spread via animals
39
What are the commonly used topical antifungals?
schedule 1 (Rx):
- terbinafine 1% (cream or spray)
- ketoconazole 2% (cream)
- ciclopirox 1% (cream or lotion)
schedule 3 (OTC):
- clotrimazole 1% (cream)
- miconazole 2% (cream)
unscheduled:
- tolnaftate 1% (cream, spray, or powder)
40
What are the less commonly used topical antifungals? (5)
- undecylenic acid (OTC)
- topical steroid-antifungal combination products (schedule 1) – ie. clotrimazole-betamethasone dipropionate (Lotriderm)
- antifungal shampoos (OTC) – ie. ketoconazole shampoo (Nizoral)
- nystatin (OTC)
- nail/lacquer solutions
41
Tinea Infection Algorithm
(options for all 3 tinea infections are similar – topical antifungals)
first line:
- terbinafine (allylamine): recommended over other agents because of once daily application and shorter duration of treatment
- clotrimazole or miconazole (imidazoles): recommended over other agents due to OTC availability, efficacy, and track record of success
other agents: (effective, but offer no significant advantages)
- ciclopirox
- tolnaftate
- ketoconazole (imidazole)
42
What should be considered when picking a dosage form?
- creams and lotions, once massaged in, allow for increased contact time compared to other products and are therefore commonly recommended
- lotions or powders may be recommended for intertriginous areas (ie. skin folds) where creams may contribute to occlusion and maceration
- powders (ie. tolnaftate) can be used as preventative agent
43
What is the duration of treatment with most topical antifungals?
minimum of 2 weeks, and continues until 1 week after lesions have cleared
- exception: terbinafine – typically applied for only one week for tinea corporis and tinea cruris
44
What is the duration of treatment for tinea pedis?
typically requires longest duration of treatment (4+ weeks)
- depends on thickness of stratum corneum
- longer treatment may be required for moccasin-like and vesiculobullous presentations
45
What is the duration of treatment for tinea corporis?
4 weeks
46
What is the duration of treatment for tinea cruris?
2 weeks
47
Clotrimazole 1% or Miconazole 2% (OTC)
- tinea cruris
- tinea corporis
- tinea pedis
- dosage forms
- population consideration and clinical pearls
- tinea cruris: BID x 2-4 weeks
- tinea corporis: BID x 4 weeks
- tinea pedis: BID x 4 weeks
- cream
- for children and adults ≥ 2 years old
- topical miconazole may increase risk of bleeding with concurrent warfarin use
48
Ketoconazole 2% (Rx)
- tinea cruris
- tinea corporis
- tinea pedis
- dosage forms
- population consideration and clinical pearls
- tinea cruris: once daily 2-4 weeks
- tinea corporis: once daily 3-4 weeks
- tinea pedis: BID x 4 weeks
- cream (schedule 1)
- ketoconazole 1% shampoo (unscheduled) for pityriasis versicolour
- not for children, ≥ 12 years old
49
Terbinafine 1% (Rx)
- tinea cruris
- tinea corporis
- tinea pedis
- dosage forms
- population consideration and clinical pearls
- tinea cruris: once daily x 1 week
- tinea corporis: once daily x 1 week
- tinea pedis: BID x 1-4 weeks (shorter duration can be considered)
- cream, spray
- not for children, ≥ 12 years old
- note the short duration and frequency of treatment
50
Ciclopirox 1% (Rx)
- tinea cruris
- tinea corporis
- tinea pedis
- dosage forms
- population consideration and clinical pearls
- tinea cruris: BID x 4 weeks
- tinea corporis: BID x 4 weeks
- tinea pedis: BID x 4 weeks
- cream, lotion
- ciclopirox olamine 1.5% shampoo (schedule 1) for seborrheic dermatitis or pityriasis versicolour
- not for children, ≥ 10 years old
51
Tolnaftate 1% (OTC)
- tinea cruris
- tinea corporis
- tinea pedis
- dosage forms
- population consideration and clinical pearls
- tinea cruris: BID x 2-4 weeks
- tinea corporis: BID x 2-4 weeks
- tinea pedis: BID x 4 weeks
- cream
- spray or powder can be used as adjunctive therapy
- children and adults ≥ 2 years old
52
Undecylenic Acid 1% (OTC)
- tinea cruris
- tinea corporis
- tinea pedis
- dosage forms
- population consideration and clinical pearls
- tinea cruris: BID x 2 weeks
- tinea corporis: BID x 4 weeks
- tinea pedis: BID x 4 weeks
- gel, liquid
- for children and adults ≥ 2 years old
53
Nystatin 100,000 Units/G
- OTC
- only effective against yeast infections, NOT dermatophyte infections
54
Topical Steroid/Antifungal Combinations
ie. clotrimazole 1%/betamethasone dipropionate 0.05% (Rx)
- topical steroid for pruritis or erythema is not suggested as symptoms resolve quickly with antifungal treatment
- some physicians may recommend low-potency steroids for extreme itchiness, but in most cases this combination is not necessary
- steroids may also introduce unwanted side effects (ie. skin atrophy) and long-term use may cause infection to spread rather than resolve due to suppression of local immune response
55
What are some patient education points?
- improvement of burning and itching will occur within few days – try not to scratch and rub the area
- ensure topical treatment is applied to entire area and extends 2 cm beyond affected area to decrease possibility of infection growth
- ensure that treatment is continued even if improvement is noted – topical treatment is typically continued for 1 week after lesion resolution for complete eradication
- tinea infections in one location of body can spread to another if care is not taken, particularly while changing clothes
- kids can return to school/daycare once treatment is started but should delay participating in contact sports such as wrestling for 3 days unless affected area can be covered
56
Follow-up Algorithm
(7 days after initiation of therapy)
no improvement:
- refer
worsening symptoms:
- refer
any improvement:
- continue until symptoms have resolved – terbinafine 1 week, clotrimazole/miconazole/ketoconazole/tolnaftate 2-4 weeks, ciclopirox 4 weeks
- continue for an additional week after symptoms resolve
57
What are the 5 efficacy monitoring points?
- lesions
- symptoms (ie. itching and burning)
- complications (ie. cellulitis)
- recurrence of lesions
- adherence
58
Efficacy Monitoring Plan
Lesions
- expected outcome
- time frame
- expected outcome: improvement in erythema/scaling/irritation, decrease in lesion size and no additional lesions
- time frame: may be seen in 2-3 days, but improvement should be noted by 1 week at latest, may take 6 weeks for full resolution
59
Efficacy Monitoring Plan
Symptoms (ie. itching and burning)
- expected outcome
- time frame
- expected outcome: improvement and/or resolution
- time frame: may be seen in 2-3 days, but should be noted by 1 week
60
Efficacy Monitoring Plan
Complications (ie. cellulitis)
- expected outcome
- time frame
- expected outcome: absence of secondary bacterial infections such as cellulitis, dyspigmentation, or other eruptions
- time frame: for duration of treatment
61
Efficacy Monitoring Plan
Recurrence of Lesions
- expected outcome
- time frame
- expected outcome: absence
- time frame: may reappear in the following few months
62
Efficacy Monitoring Plan
Adherence
- expected outcome
- time frame
- expected outcome: use of therapy for at least 2 weeks until clinical resolution and an additional week after
- time frame: for duration of therapy
63
What are the 2 safety monitoring points?
- side effects of topical antifungal therapy (burning, itching, stinging)
- hypersensitivity reactions (skin swelling, severe itching, and redness)
64
Safety Monitoring Plan
Side Effects of Topical Antifungal Therapy (burning, itching, stinging)
- expected outcome
- time frame
- expected outcome: absence
- time frame: some patients may experience side effects initially, most will develop tolerance to skin irritation with repeated use
65
Safety Monitoring Plan
Hypersensitivity Reactions (skin swelling, severe itching, redness)
- expected outcome
- time frame
- expected outcome: absence
- time frame: immediately to a few hours after product application
66
Who is systemic antifungal medication (ie. terbinafine, itraconazole, fluconazole, voriconazole, and ketoconazole) used in? (3)
- cannot use topical agents
- resistant to topical treatment
- experiencing recurrent infections
67
Tinea cruris, tinea corporis, and tinea pedis usually respond to treatment. Which patients may have relapses? (2)
- have additional risk factors
- do not adhere to recommended durations
