By Guest Blogger, Allison King, FNP-C
Tinea infections are one of the most common dermatologic conditions seen in the primary care setting. Although diagnosis and treatment may seem straightforward, providers commonly misdiagnose Tinea and overlook the optimal treatment choices. Here are 7 tips to help you correctly diagnose and treat Tinea infections.
#1: “Ringworm” is a misnomer.
Tinea has no association with worms or parasites. Instead, it represents a skin infection by a dermatophyte species of fungus. Fungal organisms are transmitted to humans by direct contact or through fomites, objects or materials likely to carry infection.
#2: Tinea Corporisdoes not usually have multiple lesions.
Tinea infections on the trunk typically present as 1, itchy, solitary, pink to hyperpigmented brown (in darker skin types), annular plaque with a dramatic, scaly border. Left untreated, the plaque expands to a larger size but does not cause additional, separate lesions to arise. What if a patient presents with multiple, round, pink, plaques on the body? Tinea is likely not the correct diagnosis. Consider these differential diagnoses:
- Nummular Dermatitis presents with multiple, quarter to half- dollar sized, pink, scaly, itchy plaques. They are typically seen on the back and lower extremities and are more common in colder weather. 2 key differences of Nummular Dermatitis are as follows: 1) it presents with multiple quarter to half dollar sized, itchy, pink scaly plaques, and 2) the plaques are evenly scaly throughout vs. having central clearing and a scalier edge.
- Granuloma Annulare presents with smooth, pink, annular plaques most commonly found on the arms, hands, lower legs, and tops of the feet. 2 key differences of GA are as follows: 1) these lesions are not itchy but may be tender or sensitive to touch, and 2) they are smooth with zero flaking or scaling.
- Pityriasis Rosea presents with round to oval, salmon colored patches and plaques with a fine overlying scale. The eruption typically begins with 1 larger plaque, the “herald patch or plaque”. After several days or weeks, new papules and plaques form over the trunk. This typically self- resolves in 6-8 weeks. 3 key differences of PR are as follows: 1) the lesions are asymptomatic, 2) are localized to the trunk, and 3) have a fine collarette of scale.
It is a great idea to review pictures of each of these diagnoses to become familiar with their clinical presentations.
#3. Topical steroids change the presentation of Tinea.
Topical steroids, including OTC hydrocortisone, may worsen or change the appearance of Tinea making diagnosis more difficult. Tinea Incognito is the term used to describe a tinea infection inadvertently treated with topical corticosteroids. It may present with a larger lesion, less redness, and more subtle scaling. Also consider that combination topical steroid and anti-fungal medications (i.e., Clotrimazole/ Betamethasone) should be avoided, since they contain a topical steroid, which increases the risk of treatment failure. Be careful to always ask about prior treatment history if Tinea is suspected. If the patient has a prior history of topical steroid application, the presentation may be atypical.
#4. Look for enlarged lymph nodes.
Tinea Capitis is often accompanied by dramatic, enlarged, cervical lymph nodes and can tip you off to the correct diagnosis moments after entering the exam room. African American children ages 3-7 are the highest risk group and often present with hair loss, scaling/ flaking/ itching on the scalp, and cervical lymphadenopathy. If a patient presents with only flaking or scaling, consider the following differential diagnosis:
- Seborrheic Dermatitis also presents with an itchy, flaky scalp. 2 key differences of Seborrheic Dermatitis are as follows: 1) it does not cause hair loss, and 2) it does not cause lymphadenopathy. If you are uncertain about the diagnosis, a KOH or fungal culture should be obtained.
#5 Tinea Capitis must be treated orally.
Topical therapy alone is insufficient for Tinea of the scalp, because fungal organisms invade the hair follicle where topical therapy is ineffective. Oral Terbinafine is the best treatment option for patients over the age of 4 due to its high efficacy and shorter duration of therapy. Keep in mind that asymptomatic individuals may be a reservoir for infection, so all household members should be treated topically with Ketoconazole shampoo. Patients should be counseled to avoid sharing hair accessories, styling tools, hats, and helmets.
#6. Ketoconazole cream is rarely the best treatment choice.
Allylamines (e.g., Terbinafine, Naftifine) are more effective treatments for Tinea infections than Imidazoles (e.g., Clotrimazole, Ketoconazole). That’s right! Ketoconazole is not the best first- line therapy and should be Rx only when allylamines are not affordable or accessible. Additionally, Ketoconazole gel is a better choice than Ketoconazole cream, because the cream can be irritating to the skin and is less effective than gel due to reduced particle absorption.
#7 Don’t forget to examine the patient’s feet.
When a patient presents with a scaly rash on 1 palm, always ask to check both of their feet. Why? Two-foot-and-one-hand syndrome is commonly missed in the primary care setting. It presents as diffuse scaling and peeling on the plantar aspect of both feet (Tinea Pedis) as well as 1 palm. All 3 locations will clear with antifungal topical or oral antifungal therapy.
These 7 tips will prepare you to diagnose and treat Tinea more accurately and effectively. My favorite resource for studying dermatologic conditions, including the diagnoses mentioned in this post, is Visual Dx. It offers very helpful images and clear, concise information about each diagnosis. www.visualdx.com
For more tips to treating common dermatologic conditions, check out our post-graduate training and education program, ThriveAP. ThriveAP spends some time covering dermatology as well as several other systems of the body in our year long program geared towards primary care. After NPs and PAs finish school, there is a lot they are expected to know in their first few years of practice. ThriveAP is meant to ease the transition into practice by providing live online webinars for continued didactic learning and mentorship. For more information, please contact firstname.lastname@example.org.
Allison King, FNP-C, studied at the University of Mississippi undergraduate and then continued on to receive her Masters at Vanderbilt University School of Nursing. She has been practicing at Mid-South Dermatology in Memphis, TN since 2008, and is a frequent speaker for ThriveAP. Allison is a member of the Memphis Dermatology Society, the Nurse Practitioner Society of the Dermatology Nurses’ Association, and serves as the regional president of the Mid-South chapter of the National Academy of Dermatology Nurse Practitioners.