🩺 Case Report: Evaluation of Acute Rash in a 54-Year-Old Female — Village Dermatology, Katy & Houston, Texas
Patient Overview
A 54-year-old female presented to Village Dermatology as a new patient with a 2–3 week history of a rash on her right arm. The rash was asymptomatic, moderate in severity, and persistent despite a 7-day course of oral antibiotics previously prescribed at urgent care.
She also reported a small irritated spot on her right cheek.
Clinical Examination
A focused examination was performed on the face and right upper extremity, utilizing dermatoscopy.
The patient appeared well developed, well nourished, and in no acute distress.
Findings:
Right proximal dorsal forearm: Patches consistent with dermatitis vs arthropod assault
KOH test: Negative for fungal hyphae, decreasing likelihood of tinea corporis
Right cheek: Mild irritation, suitable for topical steroid spot therapy
Diagnosis
1. Dermatitis, Unspecified (L30.9)
Given the clinical appearance, negative KOH prep, and healing pattern, the rash was most consistent with a resolving arthropod bite reaction or nonspecific dermatitis.
Differential Diagnosis:
Dermatitis (most likely)
Arthropod bite
Tinea corporis (less likely due to negative KOH)
Treatment Plan
1. Topical Steroid Therapy
The patient was prescribed:
Triamcinolone acetonide 0.1% cream
Apply twice daily to affected areas for 2 weeks
Avoid using more than 14 days per month
For the spot on the right cheek:
Triamcinolone 0.1% for 3 days only, to avoid facial steroid overuse.
2. Skin Care Counseling
The patient was advised to:
Use regular emollients to support skin hydration
Avoid irritants and scratching
Monitor for spread, pain, or systemic symptoms
She was reminded that diagnosis is not fully definitive, and empiric therapy plus follow-up evaluation is appropriate.
When to Call the Office:
Fever develops
Rash worsens despite treatment
New symptoms such as drainage, blistering, or increased redness occur
3. KOH Preparation
A KOH prep was performed on the right forearm lesion:
Sample collected with a 15-blade scalpel
No hyphae visualized, reducing suspicion for dermatophyte infection
Follow-Up Plan
The patient will return in 3 weeks for reassessment.
At follow-up, clinicians will evaluate:
Rash resolution
Need for additional diagnostics
Possible switch to alternative therapy if symptoms persist
⭐ Takeaway
This case demonstrates a common scenario where an acute rash may mimic infection, dermatitis, or arthropod exposure. At Village Dermatology, serving Katy, Texas and Houston, Texas, precise diagnostic tools such as KOH prep and clinical dermoscopy help guide effective, evidence-based treatment decisions.
