Nummular eczema

Devergie 1857.

Dysregulatory microbial eczema, nummular dermatitis, discoid eczema.

Chronic recurrent, often highly pruritic eczema with coin-like (nummular) foci

• Peak in frequency: 50th - 70th year of life
• Women < men.
• Prevalence: Depending on the study, between 0.1- 9.1% of the population.

• Cause has not yet been completely clarified.
• Probably polyaetiological.
• Possible triggering causes:
• Infections (bronchitis, sinusitis, dental foci, candidiasis, etc.) probably act as a trigger factor.

• Chronic microbial colonisation (streptococci and staphylococci).
• Contact allergies (bacterial antigens?)
  • Both streptococci or staphylococci can trigger the disease in the sense of an eczematous, contact-allergic reaction to microbial antigens or by a direct route.
• Atopic diathesis.
• Psoriatic diathesis.
• Xerosis cutis.
• Chronic venous insufficiency (CVI).

• Localisation
  • Mostly the lower legs are affected (think of CVI as the cause here), but the lesions can occur disseminated. The extensor sides (lower legs, upper arms, dorsum of the feet) are particularly affected

• Sharply demarcated, erythematous, scaling to varying degrees psoriasiform, sometimes crusty, often pruriginous papules, papulo-vesicles or mostly plaques.

• fAnamnesis regarding possible triggers (occupational history).
• Clinic and dermoscopy: Yellow Clod Sign, yellowish islets after wetting
• Bact. smear of nummular foci (streptococci, staphylococci), nasal vestibule smear.
• Biopsy: If possible, no sampling of the lower legs. because dermatopathologically often not distinguishable from stasis vasculitis.
• Myco-smear (native, culture).
• Focus search
  • Anamnesis: diarrhoea? flu-like infection? Burning with urination? Productive cough? Toothache? Sinusitis?
  • Lab:
    • Diff. blood count, blood sedimentation, CRP, antistreptolysin titre
  • Urine status.
  • Hemoccult (stool examination for pathogenic germs).
  • ECG
• Urease breath rapid test e.A. of a Helicobacter pylori inf.
• Focus search (lymph node palpation, X-ray thorax, upper abdominal sonography)
• Consil: ENT, dental consil, in women: gynaecological referral.
• Elevated antistreptolysin titres
• Examination for clinical signs of atopy, intradermal testing, RAST and IgE determination.

Predilection sites lower leg, back of the hand, forearms. It does not occur on the palms of the hands and soles of the feet. In children, the localisation tendency is less clear, so it can also occur on the trunk and face.

Acute or subacute eczema, oedema of the papillary dermis, perivascular lymphocytic infiltrate, acanthosis, orthokeratosis, focal epidermotropy, spongiosis, focal hyper- and parakeratosis, often reminiscent of a psoriasiform picture, no Munro's abscesses.

• Adequate hygiene
• Refatting (associated with xerosis cutis)

Mostly chronic recurrent course.

1. Gross P. NUMMULAR ECZEMA. Archives of Dermatology and Syphilology 1941;44:1060. 
2.  Fowle LP. ETIOLOGY OF NUMMULAR ECZEMA. Arch Dermatol 1953;68:69. 
3.  Aoyama H, Tanaka M, Hara M, Tabata N, Tagami H. Nummular Eczema: An Addition of Senile Xerosis and Unique Cutaneous Reactivities to Environmental Aeroallergens. Dermatology 1999;199:135-9. 
4.  Weston, W. (2016). Overview of dermatitis. Uptodate.com. Retrieved 31 May 2016, from http://www.uptodate.com/contents/overview-of-dermatitis?source=machineLearning&search=nummular+dermatitis&selectedTitle=2~19&sectionRank=1&anchor=H25#H25 
5.  Zirwas, M. (2016). Nummular eczema. Uptodate.com. Retrieved 31 May 2016, from http://www.uptodate.com/contents/nummular-eczema?source=search_result&search=nummular+dermatitis&selectedTitle=1~19