Acarodermatitis

Acarodermatitis refers to a group of skin conditions characterized by distinctive rashes that primarily affect the extremities and certain body areas, with causes ranging from genetic disorders to viral infections.

Table of contents

• Acrodermatitis Enteropathica: A Zinc Deficiency Disorder
• Papular Acrodermatitis: A Childhood Viral Rash

Acrodermatitis Enteropathica: A Zinc Deficiency Disorder

Primary zinc deficiency, Primary zinc malabsorption syndrome, Brandt syndrome, Danbolt Closs syndrome

E83.2

Acrodermatitis enteropathica is a rare disorder associated with zinc deficiency that presents with a characteristic pattern of symptoms^[1]. The condition shows a classic triad of signs: skin inflammation around the extremities and body openings (called peri-acral and periorificial dermatitis), diarrhea, and hair loss^[1].

There are two main forms of this condition. Primary acrodermatitis enteropathica is caused by an inherited defect in the protein that transports zinc in the body, which results in reduced absorption of zinc from the intestines^[1]. Acquired acrodermatitis enteropathica can develop due to insufficient zinc intake, increased body demand for zinc, problems with absorption, or certain metabolic disorders^[1].

Zinc plays a crucial role in the body as an essential micronutrient, which is a substance needed in small amounts for proper body function. This mineral is part of more than 200 metalloenzymes, which are proteins that help chemical reactions happen in cells^[1]. The body absorbs zinc mainly in two parts of the small intestine called the jejunum and duodenum. Zinc is better absorbed from human breast milk than from cow’s milk or infant formulas^[1]. Foods rich in zinc include meat, shellfish, and wheat germ, while certain substances in cereals and some medications can prevent the body from absorbing it properly^[1].

Zinc has anti-inflammatory and antioxidant properties, meaning it helps reduce inflammation and protects cells from damage. It plays an important role in wound healing, growth, brain development, and immune function^[1].

Causes and Inheritance

Primary acrodermatitis enteropathica is an autosomal recessive genetic disorder, which means it appears when a child inherits two defective genes, one from each parent^[1]. Parents who carry one normal gene and one defective gene usually do not show any symptoms of the disease^[1].

The condition is caused by mutations in a gene called SLC39A4, located on chromosome 8q24.3. This gene provides instructions for making a zinc transporter protein called ZIP4^[1][8]. When this gene is mutated, it disrupts how zinc is taken up, transported, and balanced throughout the body. The zinc deficiency in primary acrodermatitis enteropathica happens because there is a partial block in zinc absorption across the lining of the small intestine^[1].

Acquired acrodermatitis enteropathica can be associated with several situations: inadequate zinc intake from diet, such as in vegetarian diets, breast milk deficient in zinc, anorexia nervosa, chronic alcohol consumption, or intravenous nutrition without adequate zinc^[1]. Problems with intestinal absorption can also cause it, including inflammatory bowel disease, intestinal bypass surgery, cystic fibrosis, or pancreatic disease. Other causes include excessive loss of zinc through urine in nephrotic syndrome, low levels of albumin and high catabolic states from trauma, thermal burns, extensive surgery, or cirrhosis^[1].

Clinical Features and Symptoms

Primary acrodermatitis enteropathica may appear in formula-fed infants within a few days to weeks after birth, and soon after weaning in breast-fed infants^[1]. The condition affects males and females equally. Symptoms of acquired acrodermatitis enteropathica may occur at any age, depending on the underlying cause, but mostly affect older children, adolescents, and adults^[1].

Preterm infants may present early with acrodermatitis enteropathica due to increased demand and negative zinc balance at birth. In preterm infants, the condition can be due to zinc-deficient breast milk or a mutation of the transporter protein^[1].

Treatment and Management

Treatment of acrodermatitis enteropathica requires lifelong oral zinc supplementation^[5]. Typically, one to three milligrams per kilogram of zinc gluconate or sulfate is administered orally each day^[5]. Clinical improvement occurs before any significant change in the plasma zinc levels, usually within days to weeks once treatment is initiated. A clinical response is generally observed within five to ten days, and the majority of patients recover within four weeks after the start of treatment^[5].

In a minority of cases, primarily those involving other metabolic disorders such as cystic fibrosis, maple syrup urine disease, methylmalonic acidemia, or other conditions, zinc supplementation alone may be insufficient^[5]. Situations like pregnancy or stress from disease may require an increase in therapy^[5].

Additional supportive care can help with skin healing. Warm compresses to remove scale crust, followed by application of white petrolatum to eroded skin lesions, may enhance skin regeneration when used together with zinc replacement^[5].

While no special diet is required for patients as long as zinc supplementation is continued, consuming foods with increased levels of zinc can be beneficial. These include oysters, crab, beef, pork, and fowl^[5].

Outpatient follow-up care is critical for patients in order to ensure proper growth and development. Serum zinc levels and alkaline phosphatase values should be monitored every three to six months^[5].

Papular Acrodermatitis: A Childhood Viral Rash

Gianotti-Crosti syndrome, papular acrodermatitis of childhood

Papular acrodermatitis of childhood, also known as Gianotti-Crosti syndrome, is a benign, self-limiting rash that occurs in childhood^[2]. The condition is characterized by a distinct pattern of raised bumps primarily found on the face, buttocks, and the outer surfaces of the arms and legs^[2].

Causes and Triggers

The condition is associated with multiple viral illnesses. In the United States, the Epstein-Barr virus is the most commonly reported cause of papular acrodermatitis of childhood; however, in many cases, no infectious trigger is identified^[2]. The rash has been linked to many viruses including Epstein-Barr virus, cytomegalovirus, coxsackievirus, adenovirus, influenza, enteroviruses, echovirus, hepatitis A virus, herpes simplex viruses, human herpesvirus 6, HIV, mumps, parainfluenza virus, parvovirus B19, poxviruses, respiratory syncytial virus, and rotavirus^[2].

Additionally, it has been reported after vaccination, including influenza, Calmette-Guerin bacillus, diphtheria-pertussis-tetanus, poliomyelitis, hepatitis B, Japanese encephalitis, and measles vaccines^[2]. This suggests that the rash is an immunologic response, meaning the body’s immune system is reacting, rather than a primary manifestation of infection^[2].

The rash will typically appear while a child is recovering from a viral infection like a respiratory illness or stomach virus^[7]. More common in patients with a history of atopy or atopic dermatitis, the condition is most prevalent in spring and summer^[4].

Who Is Affected

The condition most commonly occurs between ages one and six years of age, though it can occur in adolescents and even adults^[4]. It typically affects children between the ages of three months and fifteen years^[11]. Women are slightly more likely to develop it than men when it occurs in adults^[7].

Symptoms and Presentation

Prior to the rash developing, children may have symptoms of a viral illness or a history of recent immunization^[4]. The rash has characteristic features: it has an acute onset and consists of raised bumps or bumps with small blisters, with lesions measuring one to five millimeters in diameter, though they may become joined together^[4].

The bumps are uniform in appearance and can be skin-colored, salmon colored, red, or red-brown. They are flat-topped and firm without scale^[4]. The rash is located predominantly on outer surfaces of extremities, buttocks, and face. It usually spares the inside of the elbows and back of the knees^[4]. It also usually spares palms, soles, scalp, nails, and mucous membranes, which helps distinguish it from hand-foot-mouth disease^[4].

The rash is distributed symmetrically on both sides of the body and is mildly to moderately itchy but not tender^[4]. Over the course of three to four days, red spots develop on the child’s skin. In most cases, the spots gradually move upward toward the face. As the condition progresses, the red spots may begin to appear purple, which often occurs once the capillaries, which are small blood vessels, start to leak blood into the affected areas^[11].

Other findings include cervical, axillary, and/or inguinal lymphadenopathy, which is swelling of the lymph nodes in the neck, armpit, or groin^[4]. Children may also experience swelling of the liver or spleen, and may have a mild fever along with the rash^[7].

Course and Treatment

Papular acrodermatitis is a self-limited and benign condition, meaning it goes away on its own without causing serious problems^[4]. The rash is not contagious, although the viral illness that started it certainly may be^[4]. The rash usually lasts about four weeks, though it can linger as long as eight weeks or even up to four months^[7][4].

The rash will go away on its own and does not typically cause scarring on the skin. There may be dark spots that remain on the skin, but they generally fade after six months^[7]. Any other symptoms will also clear up over time.

Treatment focuses on managing symptoms and includes topical emollients, which are moisturizing products, topical antipruritics to reduce itching, and topical corticosteroids^[4]. While there is no specific research supporting the use of topical corticosteroids for this condition, they are commonly used for treating rashes.