Differential Diagnosis for 67-year-old Female with Small Round Red Bumps
- Single Most Likely Diagnosis
- Eczema/Dermatitis: Given the description of small round red bumps that are mildly itchy and pustule-like, and their appearance on the panty line and legs, eczema or dermatitis is a strong consideration. The fact that it's not responding to fungal treatment but has been recurrent suggests an allergic or irritant contact dermatitis, or possibly atopic dermatitis.
- Other Likely Diagnoses
- Folliculitis: Although the patient thought it was fungal and it's not responding to antifungal treatment, folliculitis (inflammation of the hair follicles) could still be a possibility, especially if the bumps are centered around hair follicles. It can be caused by bacteria, fungi, or other irritants.
- Keratosis Pilaris: This condition causes small, rough, sandpapery bumps on the skin, often on the legs, and can sometimes be itchy. It's very common and could fit the description, although the pustule-like appearance might be less typical.
- Insect Bites: Randomly distributed itchy bumps could be due to insect bites, especially if the patient has been outdoors or in areas where insects are prevalent.
- Do Not Miss Diagnoses
- Cutaneous T-Cell Lymphoma (Mycosis Fungoides): Although rare, this condition can present with skin lesions that are mistaken for eczema, dermatitis, or fungal infections. It's crucial to consider this in the differential due to its potential severity and the need for early diagnosis.
- Cutaneous Metastases: In a patient of this age group, the possibility of skin metastases from an internal malignancy should be considered, especially if the lesions are atypical or not responding to standard treatments.
- Rare Diagnoses
- Sweat Gland Disorders (like Fox-Fordyce disease): This condition causes itchy, follicular papules, typically in the apocrine-gland-bearing areas, which could include the panty line. It's rare and mostly affects women.
- Pityriasis Rosea: Although it typically starts with a herald patch followed by a wider rash, pityriasis rosea could be considered if the distribution and morphology of the lesions fit, especially if antifungal treatments have failed.