Case

A three week old baby come to the office with the chief complaint of an extensive rash. The child seems comfortable and is nursing well. There is no history of atopy in the family. The rash is confined primarily to the scalp, neck, and axillary areas. There are waxy scaly lesions with minimal weeping. What's your diagnosis?

Newborn skin is thinner and has less hair than older infants. There is a paucity of normal protective skin flora and there are potentially vulnerable areas around the cord, scalp lesions, and circumcision for invasion of organisms. . Babies all receive some type of cord care immediately after delivery. 

Normal variations

1. Acrocyanosis-purplish discoloration of the hands, feet, and around lips in response to crying, holding breath and cold. 
2. Cutis Marmonata- bluish mottling of the skin on trunk and extremities. Common when infant is cold.
3. Harlequin Color Change- half the body red and the other pale. Benign
4. Subcutaneous Fat Necrosis- firm circumscribed nodules over bony prominence secondary to pressure. Will involute spontaneously in few months in most cases. Often associated with forcep use at delivery.
5. Miliaria- "prickly heat" Papular vesicular lesions secondary to sweat retention. Self limited and treat by keeping baby cool.
6. Milia- whitish yellow papules lesions greatest on the nose, chin, cheeks, and forehead. Secondary to retention of sebum. Usually disappear in a few weeks.
7. Neonatal Acne- papular rash that usually appears around 2-4 weeks. Probably caused by sebaceous gland reaction to hormones. May be extensive but rarely needs therapy with comedolytic agents,
8. Erythema toxicum- red macules that evolve into papules and pustules. Eosinophiles if scrapped. No therapy necessary
9. Transient Neonatal Pustular Melanosis- Vesiculopustular lesions that rupture leaving pigmented macules that eventually fade. If you stain contents, mainly neutrophiles will be seen
10. Seborrheic Dermatitis- Waxy scaly lesions greatest on the scalp(cradle cap), intertriginous areas, behind the ears, trunk, and face. Usually not pruritic and no atopy history. May have some crustiness and oozing. Early onset and lack of pruritis help differentiate seborrhea from atopic dermatitis. Treat scalp with dandruff shampoo or 1% salicylic acid in petroleum jelly and other lesions usually self-limited but may respond to mild cortisone creams or ointments. 
11. Diaper rash- wetness is the prime cause of diaper rash. Wetness leads to increased permeability of the skin to irritants and change of pH. This allows increased activity of stool lipase and protease.

1. frequent changing
2. wash thoroughly
3. gentle drying
4. avoid perfumes and harsh soaps
5. no rubber pants
6. use barrier cream
7. corticosteroids if inflammation
8. Anti-fungals if candida 
9. topical antibiotics if looks like secondary bacterial infection
10. Avoid Mycolog and Lotrisone because contain potent steroid

1. Hurwitz, Sidney. Skin Lesions in the First Year. Contemporary Pediatrics January 1993 pgs 110-123
2. Vasiloudes et al. A guide to newborn rashes.  Contemporary Peds June 1997
3. Cohen B. Another baby and another cutaneous lesion-and more on efficient recognition and mangement.  Contemporary Pediatrics October 2004