Easy Pediatrics

The word Erythema is derived from the greek word erythros that means redness of the skin. It may occur with skin injury, infection or inflammation. Erythema disappears with finger pressure (blanching), while purpura or bleeding in the skin and pigmentation do not. There are few conditions that needs a short discription here:

1. Erythema Multiforme

Acute self limiting onset of symmetrical fixed red papules , some of which form target lesions. May blister. Can show koebner phenomenon. May involve lips, buccal mucosa, and tongue.

Causes: the causes of erythema multiforme includes:

• Infections like herpes simplex virus, mycoplasma, EBV, Chylamydiae
• Drugs like sulphonamides, penicillin
• Collagen diseases like SLE, polyarteritis nodosa
• Underlying malignancy

2. Steven- Johnson syndrome

Causes are same as for erythema multiforme. Other features include

• Severe erosions of at least two mucosal surfaces .
• Prodromal respiratory illness.
• Extensive necrosis of lips and mouth.
• Purulent conjunctivitis
• Variable skin involvement- red macules, bullae, skin necrosis and denudation.

3. Erythema nodosum

Nodular, erythematous eruption on extensor aspects of legs , less commonly on thighs and forearms. Regresses to bruises. May last for 3 to 6 weeks.

Causes: may include

• Infections ; organisms mostly involved are streptococcus, salmonella, yersinea, tuberculosis, chlamydia, EBV etc
• Gut disorders like ulcerative colitis and crohn’s disease
• Malignancy like leukemias and lymphomas
• Drugs e.g sulphonamides

4. Erythema Marginatum 

Annular migratory erythema found in 10% of cases of rheumatic fever. Recurrent crops of lesions appear weekly. Associated with active cardiac disease. Continue reading »

Diaper dermatitis is caused by overhydration of the skin, maceration, prolonged contact with urine and feces, retained diaper soaps, and topical preparations and is a prototypical example of irritant contact dermatitis.

Pathophysiology

Diaper rash affects the areas within the confines of the diaper. Increased wetness in the diaper area makes the skin more susceptible to damage by physical, chemical, and enzymatic mechanisms. Wet skin increases the penetration of irritant substances. Superhydration urease enzyme found in the stratum corneum liberates ammonia from cutaneous bacteria. Urease has a mild irritant effect on nonintact skin. Lipases and proteases in feces mix with urine on nonintact skin and cause an alkaline surface pH, adding to the irritation. (Feces in breastfed infants have a lower pH, and breastfed infants are less susceptible to diaper dermatitis.) The bile salts in the stools enhance the activity of fecal enzymes, adding to the effect.

Age

Diaper dermatitis commonly affects infants, with peak incidence occurring when the individual is aged 9-12 months. One study determined that at any given time, diaper dermatitis is prevalent in 7-35% of the infant population.

Diaper dermatitis can affect persons of any age who wear diapers, in particular, elderly people.

Physical Examination