Dermatology Case Study: Treatment Of Onychomycosis In A Pati

Dermatology Case Study: Treatment of Onychomycosis in a Patient

Dermatology Case Study chief complaint: “My right great toe has been hurting for about 2 months and now it’s itchy, swollen, and yellow. I can’t wear closed shoes and I was fine until I started going to the gym.”

HPI: E.D., a 38-year-old Caucasian female, presents with complaints of pain, itching, inflammation, and a yellow discoloration of her right great toe. She reports that after showering at the gym, she experienced moderate itching which intensified over two weeks, leading her to use Benadryl cream with only partial relief. Despite persistent symptoms, she continued her gym routine, noticing worsening itching, swelling, pain, and color change in the toenail. The toenail turned completely yellow two weeks ago. She tried Lotrimin AF cream without relief and has not used other remedies.

She denies fever or chills. Her past medical history includes Type 2 diabetes mellitus. She is on Metformin 500 mg twice daily. She reports up-to-date immunizations, including the current flu shot, and moderate alcohol consumption (one glass of red wine daily). She is a former smoker. Family history includes DM type 2 and tinea pedis in her father, atopic dermatitis and hypertension in her mother. She denies constitutional symptoms, respiratory, cardiovascular, or psychiatric symptoms. Physical exam reveals bilateral cataracts, no oral abnormalities, no lymphadenopathy, and normal vital signs except for 1+ pitting edema in the ankles. The right great toe shows yellow-brown discoloration in the proximal nail, periungual inflammation, dryness, and no pus or neuro deficits.

Laboratory findings include a fungal culture confirming fungal infection. Other labs: Hemoglobin 13.2, Hematocrit 38%, Serum glucose 98 mg/dL, Lipid panel showing elevated LDL (190 mg/dL), and triglycerides (187 mg/dL). Thyroid-stimulating hormone (TSH) is normal at 3.7.

Assessment: The primary diagnosis is proximal subungual onychomycosis, a fungal nail infection. Differential diagnoses considered include irritant contact dermatitis, lichen planus, and nail psoriasis.

Paper For Above instruction

In cases of onychomycosis, particularly proximal subungual types as observed in this patient, systemic antifungal therapy is often recommended due to the difficulty in treating nail infections with topical agents alone. According to the American Academy of Family Physicians (AAFP) and Centers for Disease Control and Prevention (CDC) guidelines, oral antifungal medications are the mainstay of treatment for distal and proximal subungual onychomycosis, with terbinafine and itraconazole being the most frequently prescribed options (Gupta et al., 2014; Elewski, 2013).

In this patient’s case, terbinafine is preferred because of its high efficacy, safety profile, once-daily dosing, and its ability to target dermatophyte infections predominant in onychomycosis (Gupta et al., 2014). The typical duration of therapy for distal lateral subungual onychomycosis with terbinafine is 6 weeks for fingernails and 12 weeks for toenails, given the slower growth of toenails (Gupta et al., 2014). Since her infection involves the toenail, a 12-week course of terbinafine is recommended.

Therefore, the complete prescription for terbinafine would be:

• Drug: Terbinafine 250 mg tablets
• Strength: 250 mg
• Directions: Take one tablet orally once daily for 12 weeks
• Quantity: 84 tablets (to cover 12 weeks)
• Refills: 0 (or as clinically indicated, but typically none for initial treatment)

Alternative therapy with itraconazole could be considered, especially in cases where terbinafine is contraindicated or not tolerated. It is administered as pulse therapy—two weeks on, followed by two weeks off, for a total of three cycles—due to its potential cardiac and hepatic side effects (Gupta et al., 2014). However, given her comorbidities and the simplicity of once-daily terbinafine dosing, the latter is preferable.

Pharmacologic treatment should always be paired with patient education on adherence and foot hygiene. Monitoring for adverse effects, such as hepatic toxicity, is essential, especially in patients with diabetes, which increases the risk for peripheral vascular disease and may complicate infection management.

Baseline and Follow-up Labs and Rationale

Before initiating systemic antifungal therapy, baseline laboratory evaluation is essential to ensure safety and effectiveness. Liver function tests (LFTs), including ALT, AST, and total bilirubin, should be obtained prior to starting terbinafine because of its potential hepatotoxicity (Gupta et al., 2014). Since the patient has diabetes and hyperlipidemia, baseline renal function tests and a comprehensive metabolic panel are advisable to identify any preexisting conditions that could impact drug metabolism and organ function.

Follow-up testing should include LFTs every 4 to 6 weeks during therapy, especially if symptoms of hepatotoxicity develop, or if the patient reports symptoms such as abdominal pain, jaundice, or unusual fatigue (Gupta et al., 2014). In particular, patients with diabetes or other comorbidities such as hyperlipidemia must be monitored closely for potential adverse effects of systemic antifungals. A repeat fungal culture is generally not necessary during therapy but can be performed after completion to confirm eradication.

Additionally, baseline assessment of lipid and glucose levels, although already elevated, can help monitor the patient’s systemic control, which may influence healing. Consideration should also be given to drug interactions; for example, terbinafine may interact with medications metabolized by the CYP2D6 enzyme, although this is less prominent than with itraconazole.

In summary, baseline labs should include LFTs and renal function tests before therapy. Follow-up labs should include periodic LFTs every 4-6 weeks, titrating monitoring based on clinical suspicion of adverse effects or underlying conditions. Patient education about symptom reporting and adherence is crucial to optimize outcomes in treatment of fungal onychomycosis.

References

• Gupta, A. K., et al. (2014). Diagnosis and management of onychomycosis: new treatment options. Journal of Clinical and Aesthetic Dermatology, 7(5), 19-27.
• Elewski, B. E. (2013). Onychomycosis: Pathogenesis, Diagnosis, and Management. Clinics in Dermatology, 31(2), 165-172.
• Baran, R., et al. (2014). Update on the diagnosis and management of onychomycosis. Dermatology, 229(2), 148-154.
• Tosti, A., et al. (2014). Topical and systemic therapies for onychomycosis: efficacy, safety, and patient compliance. Journal of the American Academy of Dermatology, 70(3), 583-587.
• Gupta, A. K., et al. (2014). Systemic antifungal therapy for onychomycosis. Journal of Dermatological Treatment, 25(2), 105-112.
• Richards, R. C., et al. (2011). Onychomycosis treatment update. Journal of Cutaneous Medicine and Surgery, 15(2), 103-115.
• Scheid, P., & Baran, R. (2014). Update on management of onychomycosis. Skin Therapy Letter, 19(8), 5-8.
• Sharma, Y., et al. (2013). Treatment strategies for onychomycosis. International Journal of Pharmaceutical Investigation, 3(2), 89-94.
• Vazquez, J., et al. (2012). The role of laboratory diagnostics in the management of onychomycosis. Clinical Microbiology Reviews, 25(4), 955-964.
• Mabrouk, M., et al. (2016). Monitoring and managing adverse effects during antifungal therapy for onychomycosis: a clinical review. Journal of Clinical Pharmacy and Therapeutics, 41(4), 389-396.