What is intertrigo?
Intertrigo describes a rash in the flexures or body folds, such as behind the ears, in the folds of the neck, under the arms (axillae), under a protruding abdomen, in the groin, between the buttocks, in the finger webs or toe spaces.
Although intertrigo may affect one skin fold, it is common for it to involve multiple sites.
Who gets intertrigo?
Intertrigo can affect males and females of any age. It is particularly common in people that are overweight or obese (see metabolic syndrome). Other contributing factors are:
- Genetic tendency to skin disease
- Hyperhidrosis (excessive sweating)
What are the clinical features of intertrigo?
Intertrigo can be acute (recent onset), relapsing (recurrent), or chronic (present for more than 6 weeks). The exact appearance and behaviour depends on the underlying cause or causes.
The skin affected by intertrigo is inflamed, ie reddened and uncomfortable. It may become moist and macerated, leading to fissuring (cracks) and peeling.
What is the cause of intertrigo?
Intertrigo is due to genetic and environmental factors.
- Flexural skin has relatively high surface temperature
- Moisture from insensible water loss and sweating cannot evaporate due to occlusion.
- Friction from movement of adjacent skin results in chafing.
We can classify intertrigo into infectious and inflammatory origin but there is often overlap.
- Infections tend to be unilateral and asymmetrical.
- Inflammatory disorders tend to be symmetrical affecting armpits, groins, under the breasts and the abdominal folds, except atopic dermatitis, which more often arises on the neck, and in elbow and knee creases.
Infections causing intertrigo
Thrush: Candida albicans
- Rapid development
- Itchy moist peeling red and white skin
- Small superficial papules and pustules
Erythrasma: Corynebacterium minutissimum
- Persistent brown patches
- Minimal scale
Tinea: Trichophyton rubrum + T interdigitale
- Tinea cruris (groin) and athletes foot (between toes)
- Slowly spreads over weeks to months
- Irregular annular plaques
- Peeling, scaling
Impetigo: Staphylococcus aureus and Streptococcus pyogenes
- Rapid development
- Moist blisters and crusts on red base
- Contagious, so other family members may also be affected
Boils: Staphylococcus aureus
- Rapid development
- Very painful follicular papules and nodules
- Central pustule or abscess
Folliculitis: Staphylococcus aureus
- Acute or chronic
- Superficial tender red papules
- Pustules centred on hair follicles
- May be provoked by shaving, waxing, epilating
Common inflammatory skin conditions causing intertrigo
- Well-defined smooth or shiny red patches
- Very persistent
- Common in submmamary and groin creases
- Symmetrical involvement
- May fissure (crack) in the crease
- Red patches on other sites are scaly
- Ill-defined salmon-pink thin patches
- Common in axilla and groin creases
- Fluctuates in severity
- May be asymmetrical
- Often unnoticed
- Red patches on face and scalp tend to be flaky
- First occurs in infancy
- Common in elbow and knee creases
- Characterised by flares
- Very itchy
- Acute eczema is red, blistered, swollen
- Chronic eczema is dry, thickened, lined (lichenified)
- Acute, relapsing or chronic
- Body fluids: sweat, urine
- Friction due to movement and clothing
- Dryness due to antiperspirant
- Excessive washing
- Acute or relapsing
Allergen may be:
- Fragrance, preservative or medicament in deodorant, wet-wipe or other product
- Component of underwear (rubber in elastic, nickel in bra wire)
- Chronic disorder
- Boil-like follicular papules and nodules
- Discharging sinuses and scars
- Intermittent painful shallow blisters that quickly break down
- Rare inherited condition
- Often starts age 20–40 years
- Most troublesome during summer months
- Red brown scaly rash
- May be itchy
- Biopsy essential for diagnosis
- Dome-shaped follicular papules in armpits
- Often persistent
- Asymptomatic or itchy
- Reduced sweating
What investigations should be done?
Investigations may be necessary to determine the cause of intertrigo.
- A swab for microscopy and culture of bacteria (microbiology)
- A scraping for microscopy and culture of fungi (mycology)
- A skin biopsy may be performed for histopathology if the skin condition is unusual or fails to respond to treatment.
What is the treatment for intertrigo?
Treatment depends on the underlying cause, if identified, and on which micro-organisms are present in the rash. Combinations are common.
- Sweating may be reduced with a gentle antiperspirant.
- Bacteria may be treated with topical antibiotics such as fusidic acid cream, mupirocin ointment, or oral antibiotics such as flucloxacillin and erythromycin.
- Yeasts and fungi may be treated with topical antifungals such as clotrimazole and terbinafine cream or oral antifungal agents such as itraconazole or terbinafine.
- Inflammatory skin diseases are often treated with low potency topical steroid creams such as hydrocortisone. More potent steroids are usually avoided in the flexures because they may cause skin thinning resulting in stretch marks (striae) and even ulcers. Calcineurin inhibitors such as tacrolimus ointment or pimecrolimus cream may also prove effective.