Fifth disease

Disease Description (Causes and Symptoms)

• Definition: Intertrigo (erythema intertrigo) refers to an inflammatory rash that occurs in areas where the body folds (under the breasts, groin, abdominal folds, armpits, inner thighs, etc.) when the surface barrier is damaged by friction, moisture, and heat.
• Pathophysiology: Skin becomes softened by friction and persistent moisture (maceration), and the epidermal barrier is destroyed, resulting in localized inflammation. In a moist environment, inflammation may worsen when Candida (fungi) or bacteria proliferate.
• Main causes: Persistent friction, sweat·moisture·high temperatures, skin folds due to overweight·obesity, diaper use (infants and young children), immunosuppression (such as diabetes), prolonged skin irritation (vinyl underwear, detergents)
• Main symptoms: Poorly demarcated red rash (erythema), itching·burning sensation·pain, surface moisture·exudation, pustules or erosions, and crust formation. In cases of secondary infection, discharge·odor·severe pain or systemic symptoms may occur.

Treatment Methods

• Basic principles: Remove friction·moisture·sources of irritation → keep the skin dry·protected → medication according to whether a secondary infection is present
• Lifestyle management (priority)
  • Keep folded areas dry: Wear loose, well-ventilated cotton clothing and use clothing that absorbs sweat well
  • Lose weight (when obesity is the cause) and control body temperature·sweating
  • Change diapers frequently (infants and young children), and completely dry the skin after cleansing
  • Avoid excessive use of powder, as it may worsen the condition if contaminated; use it hygienically when necessary
  • Topical protectants: Use zinc oxide·physical barrier creams (e.g., zinc oxide) for a short period
• Medication treatment
  • Suspected Candida overgrowth: Topical antifungals (azole class: clotrimazole, miconazole, or nystatin). In extensive·recurrent cases or when immunosuppressed, oral antifungals (e.g., fluconazole) may be considered (at the physician’s discretion).
  • If a secondary bacterial infection is suspected: Apply topical antibiotics (e.g., mupirocin) or systemic antibiotics (in severe cases).
  • If inflammation is severe: Control symptoms with a short course of low- to moderate-potency topical steroids (e.g., hydrocortisone). Do not use high-potency steroids long-term in skin folds (risks: atrophy and worsening of fungal infection).
• Procedures/Surgery: Rarely, in cases of recurrent episodes due to severe chronic skin folds, weight-loss surgery or removal of excess skin folds may be considered (consult the attending physician).
• Precautions
  • Do not use high-potency steroids long-term (risk of skin atrophy·worsening of fungal infection).
  • In people who are immunosuppressed or have diabetes, infections may become severe, so early treatment is necessary.
  • Use powder cautiously together with proper hygiene.

Checklist Before an Outpatient Visit (Items to Bring·Example Questions)

• Items to bring
  • List of medications and topical products currently being used (including steroid medications)
  • History of previous skin diseases (e.g., eczema, psoriasis, Candida infection)
  • Recent blood glucose or HbA1c results (if diabetes is suspected)
  • Photographs (showing changes from the early stages of symptoms to the present)
  • Date symptoms began and factors that worsened·improved them (weight changes, use of new clothing·detergent, etc.)
  • For infants and young children: Frequency of diaper changes and products used (type of diaper·powder, etc.)
  • Whether fever·systemic symptoms are present and whether discharge (pus·odor) is present
• Key information to tell the doctor during the outpatient visit (examples)
  • "When did the symptoms begin, and which area did they start in?"
  • "Have you recently had weight changes, been diagnosed with diabetes, or received immunosuppressive treatment (steroids, anticancer drugs, etc.)?"
  • "Have you used any topical products or home remedies so far? How effective were they?"

General Example Questions to Ask the Doctor

• What are the expected effects and side effects of this medication (topical antifungal·topical steroid, etc.)?
• What lifestyle changes should I make to reduce recurrence?
• If a secondary infection is suspected, what tests (culture, KOH examination, etc.) are needed?
• Does the treatment plan change if I have diabetes? What is the prognosis?

Examples of Disease-Specific Questions

• Regarding symptoms: "Is there any white, cheese-like discharge (Candida-related discharge) or yellow pus (bacterial infection) in the rash area?"
• Regarding underlying conditions: "Do I have diabetes or an immunosuppressed condition (steroid use, HIV, etc.)? What is my recent blood glucose control level (HbA1c)?"

Additionally: Diagnosis is usually possible based on clinical findings (visual examination), and when infection is suspected, the causative organism can be identified through KOH smear (fungal), culture, bacterial culture, and other tests.