Hematogenic contact dermatitis L23.8

Contact allergic eczema characterized by great clinical diversity, triggered hematogenously (from within), in which sensitization and triggering or only triggering occurs through systemic allergen intake. The responsible allergen can be absorbed via the skin, orally, inhaled or systemically. Possible allergens include metals such as nickel, chromium, cobalt, gold, drugs, fungal antigens and food allergens. It is not uncommon for a consecutive, generalized (exanthematic) dermatitic reaction to occur.

Special forms are various forms of dyshidrotic hand and foot eczema (see below eczema, dyshidrotic) and Baboon syndrome ("baboon syndrome").

No reliable data is available on incidences or prevalences. A larger number of publications are available on the contact allergens nickel (see nickel allergy below) and Peru balsam. In most cases, proof of type IV sensitization (see allergy below) by the contact allergen in question (see allergen below) is a prerequisite for diagnosis.

Restricted general condition, fever, increased inflammatory parameters (e.g. CRP and ESR), lymphadenopathy and eosinophilia may be observed concomitantly.

Clinical differential diagnoses:

• A distinction must be made between disseminated allergic contact dermatitis (see below eczema, contact dermatitis, allergic), in which the allergen is introduced from the outside, but the contact reaction is not sharply demarcated from the healthy skin, but instead affects the non-contacted surrounding skin with "disseminated" eczema papules (for differential diagnosis see below eczema, contact dermatitis, toxic).
• Dyshidrotic allergic contact dermatitis: Following local allergen contact, a vesicular or bullous dermatitis develops on the palms of the hands and soles of the feet with clear, intraepidermal vesicles or blisters.
• Seborrhoeic eczema: mainly localized on the trunk, here in seborrhoeic zones (sweat grooves in the sternal region, along the spine, shoulder girdle) but also centrofacially. Chronic, mostly figured, slightly itchy, scaling of varying intensity, mostly localized, sharply defined, red or red-brown patches, papules or plaques.

Histological differential diagnoses:

• The histologic picture is not diagnosis-specific. Therefore, all clinical pictures with spongiotic dermatitis should be considered in the differential diagnosis.

1. Erdmann SM et al (2010) Hematogenous contact dermatitis caused by food. Allergo J 19: 264-271
2. Meier H et al. (1999) Occupationally-induced contact dermatitis and bronchial asthma in an unusual delayed reaction to hydroxychloroquine. Dermatologist 50: 665-669
3. Menne T et al (1984) Hematogenous contact dermatitis after oral administration of neomycin. Dermatologist 35: 319-320