see also:

• acute rashes in adults

• a common acquired itchy mainly truncal rash characterised by acantholysis
• described by Grover in 1970

• most often affects Caucasian men over 50 years of age with sundamaged skin
• said to occur in 0.1% of the total population with a male-to-female ratio of 2.4:1 and average age = 61yrs ¹⁾
• risk factors include sun-exposure, sweating, fever, B symptoms of malignancy, and being hospitalised or bedridden.
• a Grover-like rash has been reported during the febrile phase of COVID-19.
• increasingly reported with the use of BRAF-inhibitors
• may be more common in winter - some suggest it is 4x more common in winter than in summer
• asteatotic eczema occurs five times as often among patients with TAD as in controls
• some believe it arises against a backdrop of a xerotic epidermis with decreased sweat production rather than being caused by sweating and heat as previously postulated

• often starts quite suddenly after being excessively hot or febrile in bed
• most common sites affected are central back, mid chest, and upper arms and is usually very itchy
• may affect legs
• small, discrete, sometimes crusted, erythematous papules and papulovesicles with occasional vesicles, crusting, and erosions
• duration is variable although spontaneous self-resolution in 2-4 weeks is typical
• it is often relapsing and seasonal - 46% recurred, 11% persistent while only 43% resolved without recurrence

• 5 classical patterns which can occur separately or simultaneously:
  • pemphigus-vulgaris like (47%)
  • Darier-like (18%)
  • Hailey-Hailey-like (8%)
  • spongiotic-like (9%)
  • pemphigus foliaceous–like (9%)
  • mixed (9%)
• All variants share the common distinguishing features of acantholysis and dyskeratosis

• Galli-Galli
  • presents similarly to Grover disease in predominantly adult males as small, slightly keratotic, variably colored papules; however, focally, a reticulated pattern, as seen in Dowling-Degos disease, should be appreciated
  • Galli-Galli can affect a larger portion of the body, including the hands, groin, and lower extremities
  • histology shows similar elongation and interdigitating downgrowths of the rete ridges found in Dowling-Degos disease, and absence of the various acantholytic patterns seen in Grover disease
  • mainly appears between adolescence and middle age
  • presents with hyperpigmented macules in the skin folds
  • thought to be an allelic variant of Dowling-Degos disease (DDD) - a AD with variable penetrance hereditary condition or spontaneous mutation with frameshift or nonsense KRT5 gene mutations lead to haploinsufficiency of keratin 5, a protein that plays an important role in cell-cell adhesion, epidermal differentiation, and melanosome uptake
  • 1st described in 1982
• Epidermolysis bullosa with mottled pigmentation – as with Galli-Galli, is caused by keratin 5 mutation; has additional features to Galli-Galli of palmoplantar hyperkeratosis, bullous lesions.
• Darier disease
  • an AD genetic disorder (ATP2A2, found on chromosome 12q23-24.1. This gene codes for the SERCA enzyme or pump (SarcoEndoplasmic Reticulum Calcium-ATPase)) classified as a hereditary acantholytic dermatosis
  • typically presents with persistent, greasy, scaly crusted papules in a seborrhoeic distribution and in skin folds which usually starts from adolescence
• pemphigus vulgaris
• pemphigus foliaceous
• benign familial pemphigus (Hailey-Hailey disease)

• control fever
• avoid sun / sweating
• vitamin D
• antihistamines for relief of pruritus
• 50% of patients respond to topical corticosteroids
• sustained remission has been described after a course of systemic corticosteroids
• skin biopsy may be needed for diagnosis
• chronic severe disease may require isotretinoin or topical adapalene