A. Epidemiology

1. Affects 50% of infants
2. 5% of rashes severe
3. Peak incidence 9 to 12 months
4. Breast fed infants have fewer diaper rashes
5. Lower incidence with frequent diaper changes (mean 8 or more per day)
6. Superabsorbent disposable diapers cause fewer diaper rashes than cloth diapers
7. Fourfold higher incidence of diaper rash with with concomitant diarrhea

B. Pathogenesis

1. Urine in presence of fecal urease releases ammonium and raises diaper pH
2. The increased pH activates fecal proteases and lipases
3. Diaper area exposed to increased water loss and friction
4. Compromised skin more susceptible to biologic damage

C. Dermatoses Related To Diaper Wearing

1. Irritant Diaper Dermatitis
   1. Most common form
   2. Erythematous plaques with or without scale or macerated lesions
   3. Jacquet's erosive dermatitis is the severe form with punched-out ulcers
   4. Accentuation in convex areas: buttocks, lower abdomen, genitalia, and upper thigh
   5. Exposure to urine and stool irritates diaper area skin
   6. Infants with atopic dermatitis have predilection for irritant diaper dermatitis
   7. Increased frequency of diaper changes protective
   8. Wash skin with gentle cleanser after urination or defecation
   9. Barrier creams minimize urine and fecal contact
   10. 1% hydrocortisone topically 4 times a day for more severe rashes
2. Candidal Diaper Dermatitis
   1. Beefy red plaques with satellite lesions
   2. Predilection for inguinal creases
   3. Often follows a diarrhea episode or a course of oral antibiotics
   4. KOH scrapings of new lesion may show pseudohyphae
   5. Topical antifungals applied 4 times a day
   6. Topical corticosteroids reduces erythema and inflammation
   7. Severe cases may be complicated by psoriasiform reactions on the upper body requiring
   8. These severe cases should respond to topical steroid treatment
3. Miliaria
   1. Also known as prickly heat
   2. Multiple small erythematous vesiculopustules or papules
   3. Associated with occlusive ointments or plastic pants
   4. Self limited condition requiring no specific treatment
4. Granuloma Gluteal Infantum
   1. Purplish red firm nodules in the diaper area
   2. Represents a low standing inflammatory response
   3. Inflammation triggered by irritation, Candida, or topical corticosteroids
   4. Skin biopsy sometimes necessary to confirm diagnosis
   5. Lesions spontaneously resolve over time

D. Dermatoses Exaggerated By Diaper Wear

1. Seborrheic Diaper Dermatitis
   1. Well-circumcised erythematous and scaly plaques without satellite lesions
   2. Often concurrent scale of scalp (cradle cap), face or axilla
   3. Onset typically 3-4 months but may occur up to one year of age
   4. Treat with topical corticosteroids 4 times a day
2. Atopic Dermatitis
   1. Rarely affects diaper area
   2. Erythematous plaques with or without lichenification
   3. Causes marked pruritus
   4. S. aureus colonization and superinfection common
   5. Treat with topical corticosteroids qid
   6. Oral anti-staphylococcal antibiotics in recalcitrant cases
3. Psoriasis
   1. Rarely presents in infancy
   2. Well-demarcated erythematous plaques involving inguinal folds
   3. Scale may be absent due to constant hydration of the area
   4. Potent topical corticosteroids necessary

E. Dermatoses In Diaper Area Irrespective Of Diaper Wear

1. Langerhans Cell Histiocytosis
   1. Purpuric papules, petechiae or deep ulcerations
   2. Consider with unusually severe or recalcitrant diaper dermatitis
   3. Scalp and retroauricular areas also typically involved
   4. Associated with diarrhea, hepatosplenomegaly, lymphadenopathy, and bone involvement
   5. Skin biopsy confirms diagnosis
2. Acrodermatitis enteropathica
   1. Sharply demarcated scaly and crusted plaques
   2. Located around eyes, nose, mouth, anus, and genitalia
   3. Caused by nutritional or autosomal recessive inherited zinc deficiency
   4. Diagnosis confirmed by zinc levels less than 50 mcg per dL
   5. Responds rapidly to zinc supplementation
3. Staphylococcal pyoderma
   1. Tiny vesicles and pustules with honey crusted areas
   2. Alternately large flaccid bullae that rupture rapidly
   3. May concentrate in diaper area of newborns due to umbilical colonization with S. aureus
   4. Gram stain or culture of pustule or blister to confirm clinical diagnosis
   5. Treated with oral anti-staphylococcal drugs for a 7-10 day course
4. Congenital Syphilis
   1. Sometimes presents as eroded skin in diaper area as well as around the mouth and nose
   2. Lesions either present at birth or postnatally
   3. Dark filed microscopy of infected fluid for spirochetes
   4. Serologic confirmation (RPR, then confirm with MHA-ATP test)
   5. Treat with penicillin or alternate therapy
5. Infective Dermatitis [2]
   1. Criteria B-F are Major Criteria (Criteria B,C and F required, as well as D or E)
   2. Eczema of scalp, axillae, and groin, ear area, eylid margins, paranasal skin, and/or neck
   3. Chronic watery nasal discharge without other signs of rhinitis
   4. Chronic relapsing dermatitis with prompt response to antibiotics
   5. Usual onset in early childhood (average 2 years)
   6. HTLV-1 seropositivity
   7. Criteria H-L are minor criteria
   8. Positive cultures of S. aureus or ß-hemolytic strep from skin or anterior nares
   9. Generalized fine papular rash (in most severe cases)
   10. Generalized lymphoadenopathy with dermatopathic lymphadenitis
   11. Hyperimmunoglobulinemia (IgD and IgE)
   12. Raised CD4 and CD8 counts, and increased CD4 to CD8 ratio
   13. Treat with antibiotics
   14. Skin lesions may become less severe over time

References

1. Singalavanija S and Frieden I. 1995. Pediatrics in Review. 16(4)143
2. Manns A, Hisada M, La Grenade L. 1999. Lancet. 353(9168):1951