From the Guidelines
Exanthema is a skin rash that presents as follicular papules and pustules, typically developing in areas with high sebaceous gland density, such as the face, chest, and upper back, and is often associated with pruritus, stinging, and pain 1.
Characteristics of Exanthema
The rash is characterized by a dense, periadnexal, leucohistiocytic inflammatory infiltrate with a marked clustering of macrophages, Langerhans cells, T cells, mast cells, and neutrophils 1. The most abundant expression of EGFRis in the skin is found in keratinocytes of the basal and suprabasal layers of the epidermis and the hair follicle, leading to an EGFRi-induced secretion of chemokines and cytokines by epidermal keratinocytes 1.
Treatment of Exanthema
The mainstay of therapy for exanthema is managing the inflammatory response, which can be achieved through the use of oral antibiotics, such as doxycycline or minocycline, for at least 6 weeks, and topical low to moderate strength steroids 1.
- For grade 1 and 2 rash, continuation of the drug at the current dose and monitoring for change in severity, along with the initiation of oral antibiotics and topical corticosteroids, is recommended 1.
- For grade 3 rash, interruption of the drug until the rash is grade 1, along with a short course of systemic corticosteroids, such as prednisone, and oral antibiotics, is suggested 1.
- Additional treatments, such as oral retinoids or dapsone, may be considered, but are only supported by uncontrolled evidence 1.
From the Research
Definition of Exanthema
- An exanthem is a skin rash that may be associated with mucous membrane eruption, fever, or other symptoms 2.
- It may develop as a manifestation of an infectious disease or as an adverse reaction to drugs 2, 3.
Causes of Exanthema
- Exanthems can be caused by various factors, including viral, bacterial, parasitic, and helminth infections 2.
- Drugs, such as beta-lactams and non-steroidal anti-inflammatory drugs, can also induce exanthema 3.
- Viruses, such as Epstein-Barr virus, human herpesvirus 6, and cytomegalovirus, can cause exanthema either from the infection itself or due to interaction with drugs 3.
Diagnosis of Exanthema
- Determining the exact diagnosis of exanthema requires a careful clinical history and thorough physical examination 3, 4.
- Haematological and biochemical investigations and histology may not always be helpful in differentiating between viral and drug-induced exanthema 3.
- Serological and polymerase chain reaction assays can be helpful, although a concomitant acute infection does not exclude drug hypersensitivity 3.