Transient acantholytic dermatosis

What is transient acantholytic dermatosis?

Transient acantholytic dermatosis, also known as Grover disease, is a common acquired itchy truncal rash characterised by acantholysis on histopathology.

Who gets transient acantholytic dermatosis?

Transient acantholytic dermatosis most often affects Caucasian men over 50 years of age with sundamaged skin (mean age at diagnosis 61 years). It is less common in skin of colour, women, and younger adults.

Risk factors include sun-exposure, sweating, fever, malignancy, and being hospitalised or bedridden. A Grover-like rash has been reported during the febrile phase of COVID-19.

Transient acantholytic dermatosis is increasingly reported with the use of BRAF-inhibitors such as vemurafenib and dabrafenib monotherapy, and cytotoxic chemotherapy drugs.

What causes transient acantholytic dermatosis?

The cause of transient acantholytic dermatosis is unknown. Due to the frequent association with skin occlusion, heat, and sweating, one theory suggests Grover disease is due to sweat duct damage and occlusion.

Drug-induced transient acantholytic dermatosis may be due to the drug or its metabolites being excreted in the sweat with toxic effects on the adjacent epidermis causing acantholysis and dyskeratosis. BRAF-induced Grover disease may result from keratinocyte proliferation via activation of the MAP-kinase pathway.

SARS-CoV-2 was demonstrated on immunohistochemistry in the sweat gland epithelium and dermal vessels in a patient with COVID-19.

What are the clinical features of transient acantholytic dermatosis?

Transient acantholytic dermatosis often starts quite suddenly. Some (but not all) studies report it is more common in winter than in summer.

• The most common sites affected are central back, mid chest, and upper arms.
• Lesions are small red, crusted, or eroded papules and vesicles
• The rash is typically intensely itchy.

See more images of transient acantholytic dermatosis.

What are the complications of transient acantholytic dermatosis?

Transient acantholytic dermatosis may be complicated by the development of dermatitis, usually in a discoid pattern with round or oval, dry or crusted plaques. The plaques start on the chest and back and may spread to affect the limbs.

How is transient acantholytic dermatosis diagnosed?

Transient acantholytic dermatosis is usually diagnosed clinically, but a skin biopsy may be necessary.

The pathology of transient acantholytic dermatosis is characteristic, with acantholysis (separated skin cells) with or without dyskeratosis (abnormal rounded skin cells). Spongiotic dermatitis may also be noted. Four histological patterns are recognised, not all of which show the classic acantholytic pattern.

What is the differential diagnosis for transient acantholytic dermatosis?

• Darier disease
• Miliaria
• Folliculitis such as malassezia folliculitis or gram-negative folliculitis

What is the treatment of transient acantholytic dermatosis?

There is no curative treatment for transient acantholytic dermatosis, but the following suggestions may relieve the itch and hasten resolution.

• Remain cool, as sweating may induce more itchy spots.
• Moisturising creams or antipruritic lotions containing menthol and camphor can reduce the desire to scratch.
• Apply a topical steroid, if possible as a lotion, to relieve itch.

How can transient acantholytic dermatosis be prevented?

Keep cool and wear garments designed to prevent sweat rash.

If using a BRAF-inhibitor, the addition of a MEK-inhibitor seems to protect against the development of transient acantholytic dermatosis.

What is the outlook for transient acantholytic dermatosis?

The duration of transient acantholytic dermatosis is variable although spontaneous self-resolution in 2-4 weeks is typical. It can come and go, often with a seasonal variation. Although it is called transient, Grover disease is often relapsing and can be chronic persisting for years.