What are the causes of a desquamating rash?

From the Guidelines

A desquamating rash is most commonly caused by severe drug reactions, infections, autoimmune conditions, environmental factors, and genetic disorders, with the most recent evidence suggesting that EGFR-inhibitor-induced skin reactions are a significant cause of desquamating rash, as reported in the 2021 study published in the Annals of Oncology 1. The causes of a desquamating rash can be categorized into several groups, including:

• Severe drug reactions like Stevens-Johnson syndrome and toxic epidermal necrolysis, which typically occur as adverse reactions to medications such as antibiotics, anticonvulsants, and NSAIDs
• Infections, particularly staphylococcal scalded skin syndrome, scarlet fever (caused by group A streptococcus), and viral infections like measles
• Autoimmune conditions such as pemphigus vulgaris, bullous pemphigoid, and lupus erythematosus, which can trigger desquamation through immune-mediated attacks on skin structures
• Environmental factors including severe sunburn, chemical burns, and radiation exposure, which damage skin cells and lead to peeling
• Genetic disorders like ichthyosis and epidermolysis bullosa, which cause chronic skin shedding due to defects in skin formation
• Exfoliative dermatitis, a severe inflammatory skin condition, which can develop as a complication of existing skin diseases like psoriasis or eczema According to the 2021 study, the management of EGFR-inhibitor-induced skin reactions involves treating the inflammatory response, which is the mainstay of therapy 1. The 2011 study published in the Annals of Oncology also provides guidance on the grading of skin reactions and recommends the use of oral tetracyclines, such as doxycycline or minocycline, to reduce the severity and extent of the acneiform eruption 1. In terms of specific conditions that can cause desquamating rash, Kawasaki disease is a notable example, characterized by erythema, desquamation, and other clinical features, as described in the 2004 and 2017 studies published in Circulation 1. However, the most recent and highest-quality evidence suggests that EGFR-inhibitor-induced skin reactions are a significant cause of desquamating rash, and therefore, managing the inflammatory response is the most appropriate treatment approach, as recommended in the 2021 study 1.

From the Research

Causes of Desquamating Rash

• Desquamating rash can be caused by Staphylococcal scalded skin syndrome (SSSS), a potentially life-threatening disorder caused by toxigenic strains of Staphylococcus aureus 2, 3, 4, 5, 6
• The condition is characterized by the release of exfoliative toxins, which cause hydrolysis of the amino-terminal extracellular domain of desmoglein 1, leading to disruption of keratinocytes adhesion and cleavage within the stratum granulosum 3, 4, 6
• The toxins can be released locally, causing bullous impetigo, or systemically, resulting in a more generalized rash and severe presentation of SSSS 4, 6
• The condition can be triggered by a localized source of infection, such as a sore throat or conjunctivitis, and can be spread hematogenously to cause widespread epidermal damage at distant sites 2, 6
• The lack of toxin-neutralizing antibodies and the immature renal system's inability to excrete the causative exotoxins make children younger than 6 years predominantly affected by SSSS 5

Risk Factors

• Age: children younger than 6 years are at higher risk of developing SSSS due to their lack of toxin-neutralizing antibodies and immature renal system 5
• Underlying illnesses: adults with underlying illnesses, such as immunodeficiency or renal failure, may be more susceptible to developing SSSS 6
• Season: pediatric patients have an increased incidence of SSSS during the summer and autumn 2

Diagnosis and Treatment

• Diagnosis is mainly clinical, based on the findings of tender erythroderma, bullae, and desquamation with a scalded appearance, especially in friction zones, periorificial scabs/crusting, positive Nikolsky sign, and absence of mucosal involvement 3
• Prompt empiric treatment with intravenous anti-staphylococcal antibiotic, such as nafcillin, oxacillin, or flucloxacillin, is essential until cultures are available to guide therapy 3