Although there are a multitude of varying appearances, the<unk>  often presents with symmetrical red patches of eczema with papules and vesicles, particularly on the outer sides of the arms, face and trunk which occur suddenly and are intensely itchy occur a few days to a week after the initial allergic or irritant dermatitis. Most commonly, athlete's foot can lead to localised vesicles on hands, bacterial infections to erythema nodosum and herpes simplex virus to erythema multiforme. The diagnosis is frequently made by treating the initial triggering skin problem and observing the improvement in the eczematous rash. Both the initial skin problem and the<unk>  must be observed to make the diagnosis. Not all dyshidrotic rashes are<unk> s, but<unk> s are often dyshidrotic-like. Initial tests may include isolating a fungus by taking a swab and sending it for culture. Patch testing may be considered if there is suspicion of allergic contact dermatitis. A skin biopsy is rarely necessary, but if done mostly shows an interstitial granulomatous dermatitis, some lesions being spongiotic.<unk> s cannot be distinguished from other skin diseases by histopathology. However, they can be distinguished from other<unk> s by histopathology. Differential diagnosis Other rashes that occur in a widespread distribution can look like an<unk> . These include atopic dermatitis, contact dermatitis, dyshidrosis, photodermatitis, scabies and drug eruptions.
Id reaction
MChip
DirectHit
Endotype
Cue reactivity
Fernandez reaction
Agar dilution
Next-generation matrix